Some of the most interesting of all aquarium fish to breed are the viviparous, or live-
bearers. Although few non-aquarists realize it, many fish come full born from the bodies
of their mothers, they are born alive, and soon after birth are swimming, hiding and
eating on their own, with no parental assistance. Actually the process is not very similar
to that of mammal births. The eggs are fertilized and hatched in the vent of the mother,
after three weeks to a month or so, the young hatch inside the mother and are delivered in
to the open water as living breathing fish able to swim under their own power.
family Poeciliidae, more commonly known as “Live-bearing Tooth Carps.” These fish
derive their name from the fact that they give birth to living young. The best known of
these are the Guppies, Mollies, Swordtails and Platys. Another unusual characteristic of
this group is the capability of the female to retain the male sperm for up to as many as 8
There has been a good deal of discussion as to whether live-bearers are truly viviparous
Picture by Dr. Thomas R. Reich
(live-bearing) as are mammals, or weather the body of the mother merely serves as a
receptacle or host for the egg, which develops inside without deriving any benefit from
the mother other than protection. Although the facts vary among different species of
live-bearering fish, the majority, if not all, of the poeciliids do nourish the young while
in the early stages of development, By means of the gonopodium, which id a modified
anal fin, the male deposits his sperm inside the genital duct of the female at the moment
of contact. The sperm remains viable within the folds of the oviduct for periods of as
long as seven months. As successive complements of ova develop, the sperm fertilizes
them. In early development, the pericardial membrane is very extensive and is presumed
to be the main mechanism through which the embryo obtains nourishment from the
The young are retained inside the body of the female until they are ready to fend for
themselves. The baby fishes are expelled rolled then bent in half, but they soon
straighten out and dart to the bottom of the aquarium for sanctuary. Within a few hours
they may be observed swimming around at fantastic speeds and exhibiting amazing
acrobatics, looking for food. Occasionally females will give birth to young prematurely.
When this happens, the young have a red lump attached to the stomach. This is mostly
unabsorbed yolk sac. Many of these youngsters seem to have difficulty in swimming,
exhibiting a sort of hopping motion over the bottom of the aquarium. In many cases, the
babies manage to complete their development, and grow up normal in all respects. The
others die. It sometimes happens that less fortunate fry are born at an even earlier stage
of development. These remain curled in the position of the fetus, and die within a few
minutes of birth. These and other factors seem to indicate that the live-bearer females are
truly functioning as birth givers, not just as egg incubators, since the eggs can not be
incubated outside the female before the final stages of development.
During the development process, the young fishes are nourished by their mother. They
do not simply lie in her body protected from harm and dependent on the yolk in the egg;
instead, there are various devices in different species by which they receive nourishment
just as do the young of a mammal. All the same, they do have a yolk sac (the bag
containing nourishment is typically provided by a placenta, an organ in which the blood
of the mother and that of the young are very closely mingled without actual mixing, and
which is remarkable in that it is part of the pericardium, or membrane surrounding the
heart itself. The young fishes develop in a folded position, head to tail, and are born with
this fold still present. At birth they may sink to the bottom for a short period, but they are
usually able to fend for themselves immediately.
THE BREEDING PROCESS
The live bearing fishes are the easiest of all aquarium fishes to breed; the only problem
usually encountered is that of saving the young from the cannibalism of their parents.
They breed all the year round if kept warm and well lighted, but a deficiency of either
light or warmth can arrest reproduction completely, as also if the water is extremely acid
in ph, breeding can be lessened or completely stopped. Within the temperature range of
68F to 80F, the only influence of heat is to shorten the period of gestation.
In natural conditions, reproduction is seasonal, and the life history of wild guppies gives a
clue to reason for the development of another peculiarity of these fishes-that all, or nearly
all, require to be fertilized only once in order to produce four or five successive broods of
young. The wild male guppy is small and colorful, and he is fairly rapidly eaten by
predators, so that in the lower reaches of the streams, where these predators live and the
older guppies accumulate, it is rare to find an adult male. The larger, less conspicuous
female survivors are able to go on reproducing even though their consorts have all been
devoured. To what extent this is also true of other livebearers, which also produce
several broods from a single fertilization, is not clear.
Fortunately, the differentiation of sexes is easy in mature fish of this family. The males
characteristically possess a gonopodium, an organ of copulation which is formed from
the modified anal fin. Latest reports indicate that this pointed organ is not actually
inserted into the female tract at coition, but that packets of sperm are shot from it when it
is in close proximity to the genital aperture of the female, and that some of them find the
target. which may be why they can be observed trying over and over again.
There is often a large difference in the size of the sexes, males being smaller. This is
particularly obvious in the guppy, in which the male is also colored and may have long
and variously shaped decorative fins, whereas the female is drab. Markedly smaller
males also occur in many other varieties of livebearers as well. In Mollies, Swordtails
and platys, size differences are less pronounced, but color and finnage are usually
dramatically different. The sword of the Swordtail male and the sail fin of the Molly are
Much more is known about the inheritance of color and color variations in platys,
swordtails, and guppies than about any other species’ of fish, with the result that strains
have been established in some of them for the early recognition of sex in the newly
dropped young. This is done by color linkage; thus, before the gonopodium develops, it
is still possible to tell the males from the females, all of one sex being of a particular
color or spotted with black. In young guppies, for instance, the male will develop color
in the tail before the maturity of the gonopodium appears, allowing the breeder to
separate the sexes before unwanted breeding occurs.
Young live bearing females can be fertilized at a very early stage (in the case of platys,
some 8 days or so after birth) if mature males are present. Otherwise, they must wait for
their brothers to attain maturity, which will delay fertilization considerably. Even when
fertilized very early, the females do not bear young for many weeks and may be expected
to drop their first brood not earlier than 10 to 12 weeks of age, in the case of guppies,
platys and swordtails, and then only if kept quite warm (78F to 80F). The act of
insemination is very rapid and frequent; males take no notice of weather a female is
already pregnant or even about to drop young but pay court to anything that moves,
including other immature males. They typically hover around the female or chase her
about the tank, often with a spreading of fins and, particularly in swordtails, with a
backward swimming motion which is very characteristic. The female seems indifferent
to all this and the male simply darts in and ejects his sperm packet when the chance
The sperm are stored in the female and fertilize successive crops of egg cells for the next
5 or 6 months. If fertilization continues to occur, as, of course, it does in a mixed tank,
the new sperm certainly fertilize some of the eggs, but the extent to which the first,
original insemination can be superseded by later ones has never been fully worked out.
In the guppy, the platy, the swordtail and the Mollie, successive crops of eggs are
fertilized at discrete internals, so that one lot of young, all the same age, is produced,
followed about a month later by another batch. At an average temperature of about 75F,
the actual development of the young from the time of fertilization to birth is about 24
days, and the brood interval is about 30 days. The extra week is taken up by the
development of the next crop of eggs prior to their actually being fertilized.
THE DEVELOPMENT PERIOD
The optimum temperature for fastest development of the brood is 80F, and in bright light.
At 68F and still bright light, the interval lengthens to some 35 days or more. In dull light,
it also lengthens, and cool conditions plus dullness will stop reproduction, since this
simulates winter conditions.
In most livebearers, the pregnant mother swells unmistakably and also presents the well-
known “gravid spot” which is a dark spot near the base of the anal fin caused by the
stretching of the peritoneal wall. The female has a normal-shaped anal fin. Slightly
forward of this, inside her body appears a dark area which is known as the gravid spot. It
is, in fact, equivalent to the womb, but unlike mammals, the egg is not attached to the
mother’s body and fed by her directly. Each egg contains an embryo, and is well
furnished with nutritive elements, provided by the mothers system, on which the
developing embryo feeds during its development.
As the eggs incubate, the eyes of the fry are sometimes visible through the thin walls of
the gravid spot. To accommodate the developing eggs, the mother’s body expands,
becoming deeper and broader. A few days before delivery, she develops a bulge below
the gills, her outline becoming fairly square in this region, while the gravid spot has
enlarged its area. When the young are perfectly formed they lie in a semicircular position
and are delivered, usually tail first, one at a time, over a period of hours. On birth the fry
fall a few inches through the water, but quickly straighten out and, if strong enough,
make for cover among the plants. If these are not near by the fry sink to the bottom and
take refuge in the sand, rocks or whatever other cover there may be. They lie motionless
for a short time while gathering strength.
It is unnecessary, and in fact, inadvisable to have the male parent in the spawning tank.
Once the female is impregnated, she can give birth to as many as five or more broods of
young at intervals of four to six weeks. The number of each brood may vary from 12 to
15 babies from a young Mollie to as many as 150 young from a large swordtail.
The majority of live-bearers are born about 1/4” long, and all their fins are formed in the
normal shape. Most look like a miniature of the adult fish at birth. They are not only
much larger than the newly hatched young of egg-layers, but are also capable of
swimming and looking for food and protection. Most newly born live-bearers are large
enough not to require infusoria as first food. In a few hours after birth, live-bearer fry
can eat baby brine shrimp, daphnia and even finely ground dry food.
RECORD DELIVERIES BY LIVE-BEARERS
The largest single delivery of young by a Guppy, as far as I know, was recorded by Paul
Hahnel, the well-known Guppy breeder. Mr. Hahnel reports a brood of 170 young from
one female, although only 120 of them lived to maturity. Dr. Myron Gordon found 168
embryos in a large wild-caught Platy fish. Swordfish mature at six to eight months of age
while Guppies are recorded as deliverying their first brood when only 90 days old!
Records kept of a female Mollie show that she gave birth to 570 young, through multiple
births, in one year.
SAVING THE YOUNG FROM PREDATORS
An aquarium that contains only live-bearers or live-bearers and a few or the smaller, less
voracious egg layers may be used for breeding merely by placing a portion or two of a
fine hiding grass in a corner of the aquarium. Many youngsters soon find this natural
sanctuary and remain hidden there until they are large enough and active enough to take
care of themselves.
To preserve as many of the fry as possible, the male should be kept alone in an aquarium
as soon as she is noticeably pregnant. The best indication of this condition is the swelling
of the belly. The so-called “gravid spot”, which is a darkened area near the vent, is not
always a reliable indication.
If the mother is kept well fed and the tank has a good supply of hiding grass and fine
leafed plants, most of the fry will escape. After spawning is completed, the female can
be returned to the community tank. A permanent spawning aquarium may be maintained,
the young being transferred to a larger growing tank a few days after they are born.
These precautions to protect the young are necessary because the favorite diet of many
fishes is other fishes fry! Even mothers will eat their young if given the chance.
Various traps have been designed for the relatively rapid separation of the young from
their mother at birth. They are improvements on the old idea, which was to place the
mother in a funnel in a jar. Although she could not swim through the small hole, the
young could escape and survive. Such a restricted arrangement does not suit many
females, and it is more frequently the practice to use a small aquarium with a plastic cage
suspended in it with a slatted bottom that lets the fry escape and holds the female safely
away from them. There is also a devise that is hung right in the community thank. It is a
plastic box with a V shaped piece of plastic which separates the female from the
newborn, then after the birth, the female is removed and put back in the community tank,
along with the V shaped piece of plastic, leaving the small plastic box with the fry in it
till they grow big enough to be put in the tank. The problem with this is that there is
simply not enough room for the fry to grow in such a small plastic box. However it does
offer an outlet to observe the miracle of nature without getting a sprat tank and
Despite all these devices, most breeders prefer the more natural method of having plants
in abundance the provide shelter for the young, and removing the mother at the earliest
chance. Moving the young id not recommended at so early an age. If the mother is
supplied with more live food then she can eat, she is unlikely to destroy many of her own
young; hence the addition of live or frozen brine shrimp is recommended. If the young
have to be moved, do not use a net. Either siphon them off as gently as possible or, better
still, ladle them out with a soup ladle of a teacup. Mollies will usually not eat their young
unless they are hungry, so that if this species is well fed, the young will be present in
plenty without further precautions.
The best plants for young livebearers are masses of Cabomba, Java Moss, Java Fern,
Water Sprite, Acorus Gramineus, Cardamine Lyrata, Mriophyllum Hippuroides, Bacopa
Monniera, Riccia Fluitans, Myriophyllum, Ambulia, Nitella, Utricularia, or even algi of
certain types. They allow the young to dive in for protection but are too dense for the
adult to follow with any ease. Young born prematurely may still have a visible bulge
formed by the yolk sac and will be small. They are often poor swimmers and are likely
to die off rapidly, this is natures design. Sometimes the addition of a little aquarium salt
to the water helps, about a teaspoon to the gallon, making roughly a 0.1% salt solution
does the trick.
It is interesting to note that snails and the dwarf catfish (Corydoras) can safely be kept in
an aquarium with baby fish. You may be sure that any fry they eat are either dead or
dying. They have never been known to attack live, healthy babies.
FEEDING YOUNG LIVE-BEARERS
Live-bearer young are quite large, as young fish go, and can be fed dry or other prepared
food straight away. If they are given only prepared food, growth will be poor, but a
mixture of live and dry food is quite satisfactory. The influence of a few feeds of newly
hatched Brine Shrimp or Daphnia on the subsequent growth rate of newly dropped live-
bearers is quite remarkable, and this early feeding of live food is very important for good
development. Later in the fry’s development, live foods matter much less, although the
fishes will still do better, both in growth and healthy development, with one good portion
of live or frozen food per day.
Babies should be fed a finely ground food several times daily; six or seven times is not
too often, during the critical development stage of the first two weeks, as long as the
amount per meal is not too great. Stick the tip of your forefinger into your supply of
finely ground dry food, readily available pre-packaged at your local tropical fish retailer
under names like fist bite. A small amount will adhere to the end of your finger (which
should be well washed and dried, flick this small amount of dry food into the aquarium
and it disperses itself evenly over the surface of the water, all ready for hungry little
mouths to eat. An additional daily feeding of live or frozen baby brine shrimp or sifted
Daphnia or even Finley ground freeze dried tubiflex worms will increase the growth rate
tremendously these first few weeks.
Young live-bearers must be kept in water not lower than 75F, they can take higher
temperatures and thrive in them, and they will not tolerate cool water permanently
although, unlike some more persnickety egg-layer fry, they can take chills remarkably
well. The fry like to keep their bellies full and should go around looking like they have a
football stuffed in their stomachs for the first few weeks. They will not overeat, no
matter how they look. If much dry food is used, there will be extra fall to the bottom
uneaten which could fowl the water. Therefore, scavengers should be present, but care
must be taken as to which scavengers to use. Many catfish will not only eat your baby
live-bearers, but anything they can get in their mouths! You can be safe using snails of
the non-plant eating variety, and small corydoras, known as corys.
After the first 10 days or so, your fry will begin to look like small versions of the parents,
and become much bolder, demanding food whenever you are near the tank. At this point
it is time to graduate them to regular adult flake (freeze dried) foods which are crunched
between your fingers a little to brake up the larger flakes. You should use a “growth
food” and another variety to mix it up. At this point feed the fry dry foods 3 times a day
and frozen Brine Shrimp or Daphnia once a day. You are well on your way to a nice crop
of mature fish, and should have very little, if any, mortality from this point on.
Try not to crowd you babies too much. As live-bearers are quite prolific, there is a
tendency to breed more than one has room for. It is more satisfactory to raise a few good
fishes than to try to dispose of a lot of sickly stunted ones. Allow each baby
approximately two thirds the amount of water that it would require as an adult. A ten
gallon tank is barely enough to raise a good batch of live-bearer fry, but it will serve your
purpose. However if you put 2 or even 3 mothers broods into the same 10 gallon tank,
they will be over crowded and will, at best, grow slowly and not to full potential size, at
worst, the water will fowl and you will lose most of all your fry. In breading less is
better, and will yield far better results.
Bubbling a stream of air for the first week, followed by a bubbling sponge filter in the
baby tank will relieve some of the effects of over-crowding. Good growth is the result of
proper feeding intervals, nutritious diet, allowing ample room, proper temperature. All
these factors have been discussed. If the simple directions are followed, the results
should well justify the effort of breeding live-bearers.
GROWTH AND MATURITY OF LIVE-BEARER FRY
Given normal healthy conditions and correct feeding, the fry should double their length,
or more, in a month. By then there will be signs of sex development in some cases. The
baby fish may be returned to the community tank only when they are large enough not to
be eaten by the bigger occupants. This may mean sorting the babies into two sizes, the
smaller fry being put back into the breeding tank. It is often surprising to find that many
of the smaller fry, suspected of being runts, now put on rapid growth. This is because
they have more room ad are able to receive their full share of the food which was
previously grabbed by their larger brothers and sisters.
It is often thought that once young fishes begin to sex they cease to grow. This is not
necessarily so. Nevertheless, those which are the last to develop the gonopodium often
become the biggest. The aquarist should give adequate food and space in order to
promote early growth. An amazing fact, some cases are on record of females which, after
bearing young, have developed into males. The vast mysteries of these remarkable little
fish may never be fully realized, and are waiting for your discovery!
BREEDING LIVE-BEARERS IN OUTSIDE PONDS
In temperate zones, many of the livebearers can be bred in summer in garden pools. The
Mollies are particularly suited to this and produce extra-fine specimens as long as the
water is reasonably warm. In a good pool, they will survive at 60F quite comfortably but
will not breed unless at about 65F to 70F. It is a custom in many fish-keepers families to
place Mollies out in the spring and to net out the proceeds in the fall. A small pool of
some 450 to 500 gallons will yield 1,000 young from a stocking which contained perhaps
10 adults 6 months previously. The pond must be protected from predators like birds and
even cats, but smaller enemies such as insect larvae fail to keep up with the Mollie
production line of fry.
Swordtails, Platys and Guppies can be bred similarly, but do not take a chill as readily as
the Mollie. However, there is not the need for outdoor breeding as with the Mollie,
which produces better, larger and more exotic fishes when pond bred and raised. It is
even alleged that Sail-fin Mollies produce a worth-while crop of Sail-fin young only
when bred out of doors in the summer; I have personally experienced amazing success
with Sail-fin Mollies in summer ponds, and have never raised an impressive specimen
To some extent, all the tropicals can be acclimatized to lower temperatures outside than
they can stand inside, but they must not be suddenly subjected to them. When the fishes
are brought in again, any necessary rise must be gradual, and the best plan is to use water
from the pond in which the fishes have been kept, gradually replacing it with other water,
until you have acclimated your pond fish fully to indoor water and conditions. This is, in
fact, how most of the fish you buy in your local tropical fish store are raised. They are
bred in large pools in Florida and other areas of the world, raised in the pools and then
acclimated to indoor aquarium water, before they are shipped to your local pet store.
Stocking your garden pool or fountain with live-bearers can be infinitely more
interesting, gratifying and ultimately profitable than the standard 5 or 6 Goldfish or Koki
which is the norm. The activity of the Live-bearers darting and the constant emergence
of new life through the pond can be a joy for the whole family, and virtually maintance
free, the fry eat the natural infusoria and green water and the adults eat the misceto larva
and other water creatures, therefore only occasional feeding is necessary. At the end of
the summer, you will be surprised at the fine specimens you have created!
FORCING FASTER GROWTH FROM LIVE-BEARERS
Rapid growth is generally best, producing vigorous, well-proportioned young.
Excessively rapid growth is inadvisable, as the fishes often do badly and even die when
placed on a more normal diet and perhaps in less favorable conditions.
It is a good idea to give plenty of room and food (especially live food) and to keep the
tank warm and clean. Feed often and use aeration if there is any suspicion of
overcrowding; if much dry food issued, place snails in the tank and pay strict attention to
cleanliness. Remember that a few good feeds of live food early in development are more
important than they are later on. However restricted your live food supply may be, do not
stint the young live-bearers for the first few days.
On the other hand, even with live-bearers, which will take dry food so readily, do not
feed exclusively on live food unless you are virtually sure that there will always be plenty
available to them. Accustom them to some dry food even though there is ample live
food, or they may suffer a bad set-back if a switch-over becomes necessary. This is
particularly important if your young fishes are to pass into strange hands.
Increased length of illumination daily will keep the fish eating longer, as long as food is
supplied, but once again regard must be paid to likely future conditions. Any great
change may cause harm; therefore, if you have been forcing growth to any marked extent,
slow down the pace for a week or so before the fishes are due for a change, especially if
they are going to be shipped elsewhere, or given to friends and fellow aquarists.
BREEDING THE GUPPY
A SHORT HISTORY
While goldfish have been kept as pets for hundreds of years, the tropical fish hobby owes
its great success to the comical little Guppy – the first “tropical” fish to gain widespread
popularity. After more than half a century of cultivation, the Guppy is still the most
popular tropical aquarium fish. More than a few aquarists have been introduced to the
hobby by a gift of guppies from a friend. In his book, “Exotic Aquarium Fish”, Dr
William T. Innes refers to the Guppy as the “missionary fish” because it has made so
many converts to the aquarium hobby. But what could be unusual about a fish as
common as the common guppy?
The Guppy has been introduced to so many places throughout the tropical America’s that
it is not certain just what the original habitat of this fish was. However, most scientists
believe that the Guppy’s original home territory was Venezuela, Trinidad and the
Guyana’s. This fish is extremely plentiful in these countries. For instance, every
drainage ditch in the city of Georgetown, Guyana teems with Guppies.
Credit for discovering the Guppy is generally given to the Reverend John Lechmere
Guppy, who is supposed to have collected specimens in Trinidad in 1866. But even this
little bit of Guppy history is clouded by doubt.
This bit of Guppy lore goes something like this. About 1860, an English naturalist,
Lechmere Guppy, Sr., living in Trinidad, used to send to the BritishMuseum collections
of natural history specimens. Among some fish that he sent home was a tiny, brightly
colored little fellow that was described as a new species and named, after him, Girardinus
guppyi. After it had enjoyed years of popularity as an aquarium fish, and had become
known to aquarists by the specific name guppyi, someone discovered that the same fish,
years earlier, had been described as Lebistes reticulates. In the meantime guppyi had
been shortened to guppy, and no matter what changes are made in fish catalogues, book
on aquaria, or labels on exhibition tanks, guppies will be guppies as long as the little fish
retain their deserved popularity among fish fans. There is another fish from Trinidad
which has the official right to the name of Mr. Guppy. This is Hemibrycon guppyi, but
as it is a much larger fish than the Lebistes reticulates, is rarely seen in aquaria due to its
violent nature, and is an egg-layer, there is not the slightest danger of confusing the two.
Guppies, in spite of their tiny size, are useful citizens of whatever pond or stream they
have been introduced to and inhabit, as one of their favorite foods is the “mosquito
larvae” which they can eat almost their total weight of every day! As, in nature, this little
gem is always prolific (they are known in the West Indies as “million fish”) the sum total
of their efforts in mosquito control has made much of Florida inhabitable, as well as
many other areas of the world. The extent of their contribution is debated but they seem
as desirable in nature as they are in the aquarium.
From the beginning of Guppy culture, it was noted that males showed great variety in fin
shapes and colors. No two wild male guppies were ever exactly alike. Through the years
guppy fanciers have carefully selected until there are now more guppy varieties than
could possibly be described here. Literally every color is seen on male guppies. There is
even one variety, the golden guppy, in which both sexes are yellow all over.
Several guppy varieties are worth virtually nothing, yet are sold as feeder fish and still
fulfill a valuable purpose to the aquarist. Some males have beautiful sword like
extensions on their tails. The extension may be on the top or the bottom. It will come as
no surprise that these are called swordtail guppies. In another variety, there is a sword
extending from both edges of the tail. These are called lyre tails. Still another variety
produces males with an iridescent green netlike pattern over the tail fin and body. These
are called lace or snakeskin guppies.
But the aristocrat of guppy varieties is the veil tail guppy, prize specimens of which have
sold for more than $100.00 a pair. In the veil tail the tail has been developed into a broad
triangle, sometimes as long as the fish’s body. The dorsal fin extends back like a long
plume. Veil tails come in many exquisite colors.
The king of guppy breeders was Henry Kaufman, of Trenton, New Jersey. Mr.
Kaufman’s veil tail guppies were known the world over as the finest money could buy.
Many of the strains available today were originated by his organization. Kaufman won
so many world championships, national and local contests with his guppies that he retired
from competition in 1966.
So popular is the guppy that there are national, international, and local guppy breeders
associations. These organizations, much like rose societies and kennel clubs, exchange
information, set standards for prize guppies, and sponsor guppy contests.
The guppy may be plentiful, but it is hardly fair to refer to it as the “common” guppy.
THE BREEDING PROCEDUREHIGHBREDING OR STRAINING
The Guppy can be highbred or strained to produce a stock with a definite shade, a
particularly beautiful body color, a long flowing tail, or any characteristic that you detect
and establish as your particular goal. The following is a method for establishing a unique
strain or highbred.
The way to distinguish the young male is to watch for the development of the anal fin
which begins to become noticeably pointed even before they begin to get their color.
From a tank of young Guppies, select the males which show the strongest indications of
the dominant characterisec you wish to develop. When your selections have been made,
it is wise to separate those males from the tank, because your purpose is to mate these
males with a choice crop of females. It is then important to separate all the large healthy
females and icolate them before they can be inseminated by a male. Remember, one
mating can produce up to 8 broods, so you only want virgin females when you decide
which male to be the father of your unique new variation. It sounds harsh, but you must
eliminate the undesirable males as they develop. Allow them to mature long enough to
make sure they are undesirable in color, shape or size. You can give these less desirable
males and females to friends, after all guppies are pretty in their own way these just
aren’t what you are looking for. Or use them as feeders for your larger fish, or even
control the mosquito population in your outdoor pond or fountain!
Do not expect your first batch to produce the desired result. If your goal is a fancy tail
breed, it will be necessary to continuously repeat the above procedure after every new
batch, always selecting the best females of the last crop to be mated with the best male.
The sire of a batch can be mated back to his daughter, and even to his granddaughter, to
obtain the final desired result.
Following this general course, you can expect to have a nice thankful of top guppies in
about four or five months. At least you will be well on your way to obtaining your
individual fancy breed. For further information and more detailed methods of
hybridization, the are many booked specifically written on the subject. To really get into
guppy breeding, get involved in your local Tropical Fish Association, networking is a
BREEDING THE PLATY
A SHORT HISTORY
The platy is the pet of the aquarist who likes to experiment with breeding fish. It is also a
great favorite of everyone who likes to have a community tank. Almost any color that is
lacking in the aquarium may be supplied by one of these vivid fish. Its popularity may be
judged from the fact that most fish that have been kept by aquarists for many years have
no common name; this fish has two common nicknames, and is known by either Platy or
Moon. It furnishes an excellent example of what can be done by careful selection and in
A good example of this is the Wagtail Platy, created by accident in the New York City
laboratory of a distinguished biologist. The late Dr. Myron Gordon was a widely
acclaimed authority on the inheritance of cancer. Much of his experimental work was
done with platy fish, which are native to Central American countries in search of fishes
that had tumors or at least looked to him as though they might produce tumors.
One group of native platys brought back to the laboratory by Dr. Gordon had black edges
on the top and bottom of their tail fins. He called them comet Platys. Writing in The
Aquarium, August 1940, Dr. Gordon said, “When first we discovered the ‘comet’ Platy
in Mexico, we thought we had just another genic variety of the Platy fish’s great natural
stock of patterns. While the black margined tail of the ‘comet’ was of interest to me in
the study of fish genetics, the tropical fish dealer should not see any commercial success
for it: and, I confess, neither did I.”
However, when the biologist crossed his comet Platys with some of the varieties in his
laboratory, he was amazed. The babies produced had jet black fins and lips, with a
scattering of black on the body. Here was a variety that would appeal to aquarists, which
he named the Wagtail Platy. By careful selection, the strain was further refined until the
black on the bodies was largely eliminated. Wagtails were crossed with golden Platies
and red Platies, producing Gold Wagtails and Red wagtails.
Geneticists now know that the Wagtail pattern is caused by a genetic phenomenon similar
to one that causes Siamese Cats and Himalayan Rabbits to have dark coloring on all of
their extremities. To Dr. Gordon the Wagtail Platy was another tool to use in his
research, but fortunately he shared his discovery with aquarists. Today, Wagtail Platies
can be purchased in virtually every store in the country that sells tropical fishes; they are
nearly as common as Guppies!
THE BREEDING PROCEDURE
The Platy or Moon Fish has a short heavy body and bears little resemblance to the
Swordtail, although they are believed to be of the same genus. In its original wild form,
the Platy is an unattractive grayish fish with only a few blue scales on the sides. Some of
the original specie was found to have a red spot. However, enthusiastic aquarists have
progressed quite far in developing many beautiful color varieties by interbreeding. With
this process, those fishes which displayed the most and the brightest red were developed
into the all red variety. This same process of separation and inter-breeding was used to
develop the striking strain of Gold Platies. The color varieties of this species is too
numerous to list, however, there is always room for an addition to the list if your own
efforts of separating the desired fish for breeding brings forth unique fruit!
As is the case of the Swordtail and the Guppy, a male left in a tank with an assortment of
females, does not conceder coloring before deciding to mate. This is your responsibility,
if you have a particular goal in mind.
The adult length of the male Platy is about 1-1/2” while the female usually reaches a
length of about 2”. The Platy is usually ready for breeding in 6 to 8 weeks from birth, if
raised in an average temperature of 75F to 80F degrees, and if given plenty of room and
frequent feedings of live foods.
Platies are bred very much the same as Guppies, although, they, like Swordtails, do not
adapt very readily to the breeding trap apparatuses. For this reason, they should be bred
in a thickly planted aquarium. Unlike the Guppy, they are not as likely to eat their young.
Algae in a tank with Platies is not a problem, as they are among those fishes that do enjoy
picking at the algae, and for this reason, they make a valuable addition to a community
tank. Lively, colorful and attractive, is a good description of this fish.
BREEDING THE SWORDTAIL
A SHORT HISTORY
The Swordtail is so well-known that it is hardly necessary to describe it. It is among the
handsomest of al aquarium fishes. Both males and females of the natural wild caught
variety have gleaming, blue-green sides, with a horizontal bar of orange or red running
from the gill to the tail. The male has a peculiar tail formation – the lower part of the
caudal fin being drawn out into a sword-shaped projection, an inch or more in length and
brilliantly colored. The tail may be orange or yellow or green in nature, and is bordered
with a narrow black line.
Fry are born at intervals of four weeks, and the brood’s number from six to two hundred,
depending on the age, condition and size of the female. They are fairly hardy, and may
be easily raised in the home aquarium.
That said, it is true that swordtails are hardy, prolific, inexpensive and colorful fish, and
that many books recommend them as an essential beginners fish for a first aquarium,
however beware of this species potential violent nature. Swordtails can reach a size of 4”
to 5”; they grow big compared to many of the standard beginner’s fishes. Many of them
turn spiteful, and a rogue male frequently becomes a downright bully, constantly chasing
and worrying his smaller companions, watch for this and remove rogue males if this
occurs in your tank! After a period of time, unchecked, the aggressive swordtail will
make all the residents of your community tank unhappy, and you are apt to feel that this
is due to your mismanagement. This may lead to your feeling that tropical fish are just
too complicated for you and you give up in despair and leave the hobby. If you simply
remove the Swordtail, or any bully fish that develops, the serenity of the aquarium will be
restored very quickly, and you will continue towards being a life member of the most
exciting hobby in the world!
Nevertheless, Swordtails kept in a large aquarium with other tropicals on the larger side,
are attractive, add color and quite interesting. The most striking and unique feature is the
sword-like appendage. The sword is purely for adornment, and is never used as a
weapon; actually it is far too flexible and thin to even penetrate a piece of tissue paper!
Excluding the length of the sword, males and females are approximately the same size.
Their mouths are pointed upward, so they are inclined to eat floating dry flake food, and
seem to love it, however this versatile fish is not adv verse to scavenging on the bottom
for bits of food, and loves picking at bits of algae an the glass of the tank or on plants and
This fish seems to be eating or in surch of food most of the time, but males also spend a
lot of time chasing other fish or courting a female of their own species. When courting,
the male fully extends his fins and becomes even brighter in color, spectacular! With fins
fully extended, he darts around the female, often during these antics the male will shoot
backwards, as if presenting his sword for battle, and can dart 2 or3 times his length
backward in the process. This feet is performed with the pectoral fins, though it looks to
the entire world, and his intended female, as though his sword is letting him cut through
the water in reverse!
Here is a fun fact from the long breeding and hybriding history of this beloved aquarium
fish. The hybrid red HELLERI has been known to aquarists in this country and in
Germany for many years; in 1933 a new red swordtail came on the market and fish fans
everywhere were eager, not only to buy some, but to earn how they had been bred. It was
explained at the time that the Swordtail had been crossed with a red hybrid platy. The
Platy-Swordtail cross usually resulted in a pretty, red and black motted fish. In breeding
these fish, and from such constant experimenting the red helleri or red sword was slowly
There was considerable mystery about the origin of this strain. It is said to have appeared
in an aquarium belonging to an old lady in New York – another one of those happy
accidents that are as likely to happen to amateurs as to professionals. The ledged
continues, she made a minor fortune on the red unique variety, selling specimens for
$20.00 to $30.00 each in 1930’s dollars! This, more vivid red swordtail bred true,
meaning that it was not a sterile fish (unable to re-produce) and the fry were mostly just
like the vivid parents. Both males and females are a glowing, burnished red – a color that
completely covers the back and sides of the fish and continues seamlessly into the
beautiful, black-bordered tail-fin of the male. Today it is known as the red velvet sword,
available almost everywhere fish are sold, however it was never awarded a specific
scientific name, since its true origins have never been conclusive proved. There, tell that
one to your know-it-all aquarium buddy!
THE BREEDING PROCEDURE
AS IS THE CASE WITH THE Guppy, it is possible to separate the color varieties in
order to establish a particular color strain. Separation of a favored male to be mated with
a female of a particular color is necessary because of several varieties are kept in the
same aquarium; the males will not necessarily seek out females with their own coloring
The rate of maturity in swordtails is extremely variable. The anal fin of the male,
modified to form the gonopodium, may develop in 3 months in some fish, while in others
of the same batch, it may take as long as 6 ½ months for the same degree of development.
Little if any growth can be expected once the sword has fully developed, no matter how
much or how often they are fed from that point on.
Since the average length of the tank raised full grown Swordtail is about 3 inches (up to 5
in the wild!) in order not to overcrowd the young, you should allow about twice as much
space for 100 Swordtail fry as for the same number of Guppy fry. If the extra space is
not allowed, the Swordtail is prone to dwarfism and full growth potential will probably
not be reached.
The Swordtail, admired for his flashy liveliness, is second only to the Guppy in
popularity as a primmer on breeding, because of the many unique and striking color
varieties that can be obtained by careful straining. The female may deliver anywhere
from 100 to 200 babies per batch. When two males are kept together, one usually
assumes the role of bully. This problem is minimized, however, when 3 or more males
are kept together.
During the breeding process it is not advisable to use the breeding trap for the female, as
she becomes panicky if confined any length of time in too close quarters. In her effort to
free herself, there is always the possibility of injury, or in many cases, ich, fungus and
often death. Avoid breeding traps with this fish at all costs.
General feeding and breeding instructions for the Swordtail are the same as those
mentioned for most live-bearers. The Swordtail should have a generous amount of live
and frozen foods, but they do well on prepared dry and freeze dried foods as well.
Frequent feeding of the baby Swordtails is necessary in order to satisfy their robust
appetite. At birth, the babies are quite a bit larger than the Guppy fry, and much more
aggressive. Kept together, the Swordtail fry may eventually harm or kill the Guppy fry;
however the Guppy fry will grow at a much faster rate for the first 4 weeks and therefore
may be kept together for a limited time with few ill effects.
In short, Swordtails are prolific. A large female may produce a brood of up to 250 fry at
one time. The young are born about ¼’ long. They are robust and easy to rear. In order
to obtain large specimens it is necessary to give plenty of food, warmth and space, so that
the fish can grow as much as possible before the males develop a gonopodium, and later
the stare of the Swordtail, which effectively ends the growth process.
BREEDING THE MOLLIE
A SHORT HISTORY
The Mollie or Mollienesia, as it was originally classified, has some of the most beautiful
and unusual varieties of Live-bearer fish available today. Indeed, the Sail fin Mollie is
arguably one of the most beautiful and exotic fish available of any species. However,
Mollies are perhaps the most difficult of all of the common Live-bearers to keep, under
the normal recommended community tank conditions, they seem to quickly become
sickly and soon die. They are arguably the most delicate of live-bearers, when chilled or
otherwise exposed to environmental stress of any kind, they tend to develop an ailment
known commonly as “shimmies”. In reality, this is not really a disease but merely
symptoms of stress, mush as some salt water fish would display under similar
circumstances. A Mollie with “shimmies” rocks back and forth and seems to be
shivering, it appears to be swimming but not getting anywhere, also its fins appear tightly
clamped to its body. If nothing is done, the Mollie will die very shortly, however,
remove the stress and the condition corrects itself remarkably fast. Two things need to be
done, first raise the temperature to the high 70’sF, and second add one to two teaspoons
per gallon of salt to the water. I mention this, because Mollies have discouraged many
the new aquarists and yet is so common a problem, not your fault and easily avoided.
The sail fin mollies are among the most dramatic of all livebearers. They are also the
largest and most difficult to maintain. Mollies normally inhabit brackish (salt/fresh water
estuaries) environments, and do best in captivity in hard, alkaline water with added salt.
In nature they are nearly exclusively plant and algae eaters, so they must be fed lots of
sperilina, even boiled spinach Finley chopped, to remain healthy. Sail fin Mollies are
available in several color varieties. Only males have the “sail fin” and can grow up to 5
inches in the wild. Although these fish breed readily, young raised in tanks rarely
develop the “sail fin” and in fact only reach about 3-31/2 inches in length.
The genus Mollienesia, from which the name molly was derived, has been re-classified as
Poecilia and considered to be in the same genus as the Guppy. For years it had been
noticed that the guppy will, under certain circumstances, interbreed with the Mollie, and
now the close relationship between the two has been confirmed.
The native habitat of these fish extends from the southern United States to the Yucatan in
Mexico, and they occur mainly in brackish estuaries. Their maximum length is about 5
inches, but in the aquarium they only reach about ¾ of its potential length. They like
plenty of warmth, a temperature of at least 79F is recommended. They are not very
aggressive, but can protect themselves, so they are suitable tank mates for almost all
tropical community tank fish. Mollies require a well lit tank with plenty of live plants
(which they will eat) and some alga is always recommended. They are not, in any way
demanding when it comes to water quality, however the addition of sea salt at the rate of
1 teaspoon per gallon is recommended. The sail fin Mollie must be given at least a 20
gallon long to swim in or he will probably never show the beautiful sail fin, and will
diminish in health and eventually die.
The Black Mollie is one of the hardiest of all Mollies available for the beginner. This
hardy little fish has been created and line breed for the community tank for so many
years, that most have lost their special needs and get along just fine under normal
aquarium environments. This species looks nothing like its ancestors in the wild, where
they are an extreme rarity, a mutation of the Sphenops Mollie, which is a black and silver
speckled fish, found in the Everglades of Florida, among other places. They have been
inbreed until now the line, for the most part is velvety black all over, even the eyes are jet
black. They should produce jet-black young which retain their color, and should not
become speckled as they grow. The fry are absolutely stunning, actually miniature black
versions of the parents as soon as they are born, and are among the hardiest and largest of
When feathery plants such as Myriophyllum become coated with algae the best natural
method of cleaning off the algae is to put the bunch into a tank containing Mollies. These
fish will eat every scrap of algae, and yet not damage the fine fronds of the plant.
The original Sphenops Mollie, which is still popular with aquarists, is motted black and
silver. The posterior edge of the tail of the male is usually bordered with yellow or
orange. The dorsal fin of the Spenops does not in any way appear as a sail fin.
The true, or as found in nature, Sailfin Mollie, is quite a remarkable fish. Individuals of
both sexes have a dorsal fin that seems joined to the caudal fin, when the male displays
his “sailfin” when courting a female or fighting with other males, to become rigged like a
sail boat’s mainsail! The native Sail fin Mollie is a true brackish-water fish and are
sometimes even spotted by swimmers, and divers in coral reefs like Key WestFlorida,
Where they may display two kinds of behavior. Either they are busy searching endlessly
for some food at the bottom of the sea, coming and going, digging about in the sand. Or
they are swimming about peacefully among the rocks and other fish, meandering at a
thoroughly nonchalant pace, gracefully extending their large fins like ballet dancers. In
the wild, everything about their demeanor makes the viewer think of a dance. To really
see these remarkable fish display their “sail fin” it is recommended that two or more
males be put in the same tank along with several females. The males threat displays, by
raising and stiffening the dorsal “sail fin”, which is truly a sing to behold over and over
again, is epically prevalent in the presents of another male, since males tend to be
aggressive towards one another.
Another interesting strain is the “Midnight Mollie”, sometimes known as the Black Sail
fin Mollie; they are not a separate species as is generally believed. Originally most were
produced by crossing the Velifera or Latipinna (the two kinds of Sail fin Mollies) to
mutant black Sphenops found in nature. The resulting fry bore larger dorsal fins and had
black speckled bodies. Further line breeding with the blackest specimens finally
produced the all-black body and the large dorsal. Nevertheless, throwbacks occur, and
many beginners are disappointed when an expensive pair fails to produce many sail-
finned perma blacks. Owning to the original crossing, some of the young may be born
black or mottled; many as they grow become more bottled and remain so. A very few
turn jet-black all over and row to a large size.
You may have seen some through-backs to these experiments among commercial
breeders, in your local pet store. In a tank of “common” Black Mollies, you may find
what is known as a “black Sail fin Mollie”; the choicest specimens have a huge black
dorsal fin which is bordered along the upper edge with orange gold. This looks entirely
different from the natural Sail fin Mollie, the fish is usually 3’ or less in size and the “sail
fin” it is more like a slanted rectangle with a point at the end facing behind the fish. The
“sail fin” can not be unfurled as Ridgeley as their much larger brothers They are rare,
beautiful and hardy anomalies, which are a real showstopper in the tank, but you will run
across one usually by lucky accident, buy it when you see it. Unfortunately, Mollies soon
become in-bred, and the progeny tend to get smaller and smaller with each generation.
Before this occurs it is advisable to introduce new blood, but this must come from good
stock if first-class features are to be maintained. Like their larger brothers, the natural
Sail fin Mollies, the largest sail fins are bred and reared in warm outdoor pools: few tank-
raised specimens ever attain great size, or the magnificent dorsal fin.
In short, all of the Mollie species have been interbred, resulting in many different color
varieties and finnage shapes. We now have the solid black mollies, both sail fin type
with orange-bordered dorsal fin and the sphenots, or common variety. There are other
black aquarium fish but no freshwater fish approaches the velvety black texture of the
Black Mollie. Albino forms with red eyes, there are true lyre tails in most every color,
even chocolate ad orange! Mollies, like Guppies, can be acclimated to full strength sea
water. They enjoy eating algae growth in the aquarium, and will graze endlessly on it,
looking for choice patches to nibble. IF your tank lacks algae, you must provide
“sperilina” flakes, special commercial Mollie food, or small amounts of chopped boiled
spinach. Mollies are found from Southern United States down into Central America.
They live in brackish and fresh water in nature, and can even be found in the ocean, in
full salt water, off the Florida Keys!
THE BREEDING PROCEDURE
The Mollie is the largest in size of the “common” livebearer in terms of both length and
girth. This size (up to five inches in length and 1 inch in body height, two inches in
height on the sail fin variety) however, is usually only obtainable if purchased from
stocks that come from commercial “pool” fish breeders in Florida, which is one of its
native habitats. When a Mollie is bred in the average size home aquarium, it rarely
reaches its full size, unless it is given a great deal of space which it needs for grow out.
While they can be conditioned to fresh water, the addition of one tea-spoon of sea salt to
each gallon of aquarium water is recommended. Only add additional salt when doing a
physical water change, not when topping off the aquarium. Salt is cumulative and does
not evaporate, so unless you physically remove a gallon or five gallons of water and
replace the same amount with new water (to which you have added 1 tea-spoon of salt),
do not add more salt. The eventual effect of adding salt when simply topping off the
aquarium will be to quickly develop a salt water aquarium, killing your plants and non-
brackish water fish. Beginning to see why this may not be the ideal beginner fish?
Each succeeding generation of Mollies bred in the captivity, declines in vigor and size
when bred in fresh water, but if returned to salt water, and allowed to breed, the young of
that batch will regain the original size and vigor. Because of its need for partial salt water
and high temperature (80F or higher), and their absolute need for plant matter to eat, it is
not advisable to put the molly into a community tank. This said, many have experienced
having a very healthy pair in a normal community aquarium with no added salt and have
fed then a regular community tank flake food, and scene the Mollie pair happily dart
about for a year or more, but the chance is, you are better of with other fish to start with.
The Mollie also thrives very well on algae, and for this reason, we make an exception and
recommend a sunny location for the molly tank, to encourage natural green algae.
However, while algae is more important to them than foods which are fed them, it is still
no more important to them than foods which rich in protein, such as commercial freeze
dried flakes and supplement with live or frozen brine shrimp occasionally. A helpful
addition to their diet is an occasional small portion of boiled spinach and oatmeal.
The one exception to the rule is the very easy to keep Black Mollie, which has been
strained and refined over the years by commercial fish to the point that it is easily kept
under normal community aquarium conditions, breeds readily and has some of the most
unique fry you will ever see. Depending on the strain, they may be born up to 3/8 of an
inch in length, and as large overall as 2 week old well fed guppy! They are also unusual
because strains are born jet-black and a perfect miniature of the adults.
The Black Mollie is a beautiful, velvety, coal or jet-black fish, whose color is due to a
condition of the skin pigments called melanism(in laymans terms, the opposite of
Albinoism). In some strains, the male has a large black pointed ploom for a dorsal fin
with an edgeing of orange yellow, a through back to an attempt at breeding a true black
sail fin variety.
Good news, in the female, the urge to devour their young is not very strong, although she
is known to do so. The female becomes very delicate when she is bearing her young, and
it is advisable to remove the other fishes from the tank of the pregnant female, rather than
risk premature birth of the fry, or even her death, by moving the heavy female into a
breeding tank. If you have a well planted empty tank that you intend to use to raise the
molly fry, the female should be moved well before the final stages of pregnancy. One
thing for certain, you should never use a breeding trap with Mollies, you will find she is
very uncomfortable and sometimes literally beats herself to death against the restrictive
sides of the small box, or gives premature birth to dead little egg looking fry, that could
have been saved if born into a planted tank environment.
When born, the young, who are usually, but not always, quite large, are capable of taking
care of themselves, especially if the aquarium is heavily planted. The young grow fast by
comparison to Swordtail fry. They should be fed baby brine shrimp and Finley ground
freeze dried foods the first week, followed by a variety of foods for a growth regiment the
next week. They should be fed small portions 5 or more times a day, in a variety that
includes sperilina, protein and live food. For maximum growth and health of the fry,
their rearing tank should have an abundant supply of algae, left to grow on rocks and the
sides of the tank.
With the exception of the “common” Black Mollie, this is one of the most challenging of
the livebearers to breed and rise to adulthood. If you find real interest in this unique fish,
and really want to try your hand at breeding and experimenting with straining, you may
want to conceder the outdoor pond method explained earlier. The Mollie is most suited
for outdoor pond activities, as long as the water remains 75F or above, have fun, all
livebearers will breed and give you hours of pleasure, no matter how much work and
challenge they represent, the fish will give back what you put in, above all, enjoy
A CURIOSITY OF THE LIVE-BEARER WORLD
The Half-beak or Dermogenys/Belonesox
A SHORT HISTORY
Two very strange live-bearing fishes that are sometimes kept in an aquarium are
Dermogenys and Belonesox. The family Hemiramphidae (Half-beaks) is common
throughout tropical seas, but Dermogenys pusillus inhabits the brackish rivers of Malay,
Siam and the Dutch East Indies. These unusual fish can be kept and bred in a fresh-water
aquarium, especially if a little salt (a teaspoon per gallon) is added. The lower jaw is
fantastically prolonged: if both jaws were the same length the fish would appear to have a
long beak; as it is, it only has “half-a-beak”, thus the common name. The halfbeak is a
superb fighter, the second in ability only to the fighting fish itself. The people of
Thailand have for many years bred halfbeaks for fighting, until the present cultivated
strain far outperforms its wild counterpart.
Fights are staged in this way: Two halfbeaks are placed in a shallow earthenware bowl,
filled with a few inches of water. The fish eye each other for a moment and then close in
for the attack. They may lock jaws and shake and roll over. Or one fish may clamp its
large jaws over the other fish’s head. Obviously, the fish that grabs the other has a
temporary advantage. Such “wrestling” sometimes continues for hours, until one of the
combatants becomes too exhausted to continue. The one that gives up is the loser, and
the men who have placed their bets on this fish lose as well. Occasionally, both
contestants become exhausted at the same time. That is, the fish administering the most
holds during the fight scores the larger number of points and is declared the winner!
In Southeast Asia and the East Indies, where the halfbeak is native, it is a valuable eater
of mosquito larvae. If the quiet streams, ditches and ponds where the halfbeak lives were
without this fish, the mosquito population world undoubtedly become unbearably large.
Halfbeaks make interesting aquarium pets, and they ordinarily do not fight with other
kinds of fishes their own size. However smaller fishes are likely to be eaten quickly!
THE BREEDING PROCEDURE
It is not at all a beautiful creature to have about the house, nor is it an easy fish to breed in
captivity, but there is a certain fascination in watching anything as weird as this. The
adult male is about three inches long and the female, who is considerably larger, produces
young in litters varying from one to thirty at a time, which are anywhere from 4/4 of an
inch to over and inch at birth! The babies grow rapidly, especially if there are plenty of
live plants for them to tear up and devour, and begin to develop the half –beak when they
are about four weeks old. The tank must be thickly planted so that the babies can hide
away in the green water-grass before their parents can eat them.
Since the males, when two or more are together, will fight, sometimes to sever harm or
death, it is best to keep only one male with several females for breeding purposes. The
females are easily recognized by their fan shaped anal fin. For a successful brood, the
pregnant female must be left undisturbed; in favorable conditions, not in a room with
traffic, but away in a private corner. The female may bred every 4 to 8 weeks. Before
she gives birth, put brown tater around the bottom half of the tank or the babies may
swim into the glass not seeing it and damage their prominent jaw. You can also help to
avoid this problem by using aquatic plants to form the borders or confines of the tank.
You can only keep these fish if you have a constant supply of live food for then such as
guppies or tadpoles. Without constant live food of substantial size, they will quickly die.
Many breeders keep a tank of these unusual fish around the breeding room to dispose of
their cull fish. Many fish fans hate to use live fish as food, but true aquarists and breeders
know that this is only a part of nature.
LAST NOTE ON LIVE-BEARERS
Remember, the Shedd Aquarium in Chicago in 1933 made a chart calculating the number
of young a pair of Guppies may produce in one year, under perfect conditions, and if all
young were to survive and prosper. Allowing for a litter of only fifteen every four weeks,
and for ten of the fifteen being females, one original pair might produce 2,244,600
Guppies in just 365 days! Perhaps it is just as well that the mortality among these
underwater infants is high in spite of the aquarist’s care! It is important to remember in
breeding, nature provides virtually unlimited new life for us to choose the very finest and
help improve the strain and keep it strong. If the breeder does not constantly cull his
troops of young, keeping only the very finest examples form each batch, the strain will
quickly weaken and your results will falter. What you do with the culls is up to you, but
if you kept each and every fry born to maturity, you would quickly be run out of your
home by endless tanks of fish you really don’t want. Many outsiders call it brutal, but it
is just an imitation of nature. Our morals are based on one young life born in a year;
nature has blessed the live-bearing fish with hundreds to choose their one replacement
each year. With a lot of practice and a little luck, generations of aquarists in the future
may look to you as the father a unique variety of a very special fish!