Tropical Aquarium Fish Halfbeak: A Fun Aquatic Fish for the Home Aquarium



Halfbeak fish as explained by Dr. Thomas R. Reich


The Half-beak or Dermogenys/Belonsox



Halfbeak Fish as explained by Dr. Thomas R. Reich

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 inhabit 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.

Halfbeak Fish as explained by Dr. Thomas R. Reich

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 who 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!


Halfbeak Fish as explained by Dr. Thomas R. Reich

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 would 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!

Halfbeak Fish as explained by Dr. Thomas R. Reich





Halfbeak Fish as explained by Dr. Thomas R. Reich

The Halfbeak 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 1/4 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  in the green water-grass before their parents can eat them.

halfbeak giving birth halfbeak 8

Halfbeak Fish as explained by Dr. Thomas R. Reich

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 paper around the bottom half of the tank or the babies may swim into the glass not seeing it and damage their prominent jaw.  This problem can be avoided by using aquatic plants to form the borders or confines of the tank.



Halfbeak Fish as explained by Dr. Thomas R. Reich

To keep these fish it is necessary to have a constant supply of live food for them 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” or less than ideal fish in this manor.  Many fish fans hate to use live fish as food, but true aquarists and breeders know that this is only a part of nature.

Halfbeak Fish as explained by Dr. Thomas R. Reich


Dr Thomas R Reich PhD

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Posted in Fresh Water Tropical Fish, Unusaul Aquarium Fish

Giant Danio – Danio Balabaricus

breeding the giant danil with Dr Thomas R. Reich

breeding the giant danil with Dr Thomas R. Reich

Danio Balabaricus –  Giant Danio

By:  Dr. Thomas R. Reich PhD


General Information on Giant Danio

The Giant Danio or Danio Balabaricus belongs to the family Cyprinidae and was first imported in 1909. breeding the giant danil with Dr Thomas R. ReichAs its name   suggests, this is the largest of the Danios; it used to be known under the scientific name of Danio Malabaricus. The Giant Danios originates from southwestern parts of India and Sri Lanka.  It is pale blue in color with three or four pale yellow stripes or blotches   running down the sides of its body. The dominant individuals in a group of these fish will be the dominate male, and this fish should be selected for breeding.

Further, the body is slim, elongated, strongly compressed at the sides, and up to 4 inches   long. The back is steel-blue, the flanks greenish, behind the gills there are two to three   transverse golden bars, and the sides are decorated with blue and goldfish longitudinal   stripes. The male is usually smaller and has more distinctive coloring.  In the spawning   season he has orange pectoral fin.

breeding the giant danil with Dr Thomas R. Reich

In its natural surroundings in India, it is quite common and lives in clear, stagnant and running waters along the Malabar Coast, and grows up to 8 inches in length, but that would be an exceptional specimen even in a large stream. Tank raised specimens will rarely grow larger than 4 inches. The mouth has two sets of barbells, although captive specimens are usually missing the barbells on the upper jaw.

In spite of its large measurements, this fish can be kept with other, smaller species. An extremely peaceful fellow, it is very tolerant of other fishes in its environment. It very  much appreciates a little morning sunlight in its tank!


Sexing a Breeding Pair of Giant Danio

breeding the giant danil with Dr Thomas R. Reich

The sexes are easy to tell apart by the slimmer, more attractive appearance of the male, and the “stuffed” belly of the female. This Danio is known for its incredible speed,   noticeably faster than that of other species. It is practically impossible to remove this fish from a well planted community tank without creating a great deal of disorder, unless you take its flight direction into account and capture it between the net and the receiving jar or second net.


The Breeding Process of the Giant Danio

breeding the giant danil with Dr Thomas R. Reich

The breeders, 1 female and 2 females should be conditioned on live food and kept   separately for 7 to 10 days. Set up the breeding tank (at least 10 gallons, though 15 or 20   long is ideal) the same as with Zebra Danios, with the marble bottom, however, the water   depth needs to be 8 inches, and you must add several nice clumps of fine leaved plants.   The manner of fertilizing the eggs is characteristic of other Danios, and a steady   temperature of 75F t0 79F is great. However, during mating, the male pushes himself   against the female and brings his anal fin, which he has rolled up into a kink of a bag,   under the female’s anus.

breeding the giant danil with Dr Thomas R. Reich

The eggs are caught in this “bag” and are fertilized at once.   The male then scatters the fertilized eggs among the plants. The number of eggs per   meeting is small – only 5 to 20, but this process is repeated many times over about a 2   hour period and a total of 200 to as many as 400 eggs are produced fertilized and laid.

breeding the giant danil with Dr Thomas R. Reich

The eggs are clear as glass, not adhesive, so most will fall through the plants into the   marble base and be fully protected from the breeders. The eggs measure about 1mm in   diameter, much larger than the Zebra and its other close relatives. Once the breeders   activities have stopped remove the breeders at once.

breeding the giant danil with Dr Thomas R. Reich

After two days after the eggs have been laid, the first young fish appear. Depending on   various factors, however, it can take as long as a week before the last egg has hatched   out. Temperature is not the least of these factors.


Just How Hardy are the Giant Danio Fry

I once had an interesting experience with a group of Danio’s I was breeding (a trio of   Long fin Blue Leopard Danios). I set up the breeding tank in the usual way, and after a   day or so, I was convinced the fish had not bred. I thought, since they were a very fancy   strain, something had gone wrong and that they had failed to breed. I returned the   breeders to the conditioning tanks, and dumped the water in the tank, setting outside in   the cold, about 41F at night for a day, then brought the tank back in to prepare it for   breeding again, this time Fire Neons.

breeding the giant danil with Dr Thomas R. Reich

I decieded not to sterilize the marbles on the   bottom and to just fill the tank with fresh aged water. On the evening of the second day,   the tank was filled with the aged water, and readied for breeding. The temperature was   raised to 75F for breeding the Fire Neons and the breeders introduced the evening of the   fourth day. The next morning, when I was observing the behavior of the pair of Fire   Neons, I observed hundreds of slivers hanging from the glass sides of the tank. Not knowing what was actually going on I removed the Fire Neons. I did not know if the fry   were fast hatching Neons or what? I decided to raise the fry and as the days passed other fry appeared.

breeding the giant danil with Dr Thomas R. Reich

I raised the young and both the Blue Longfined Leopard Danios and Fire Neons grew up   happy and healthy together! This shows that the fry of the Bracydanio and Danios   species are much heartier than anyone could have expected, left with nothing but the   slightest amount of moisture for over 24 hours and exposed to temperatures as low as   41F, the eggs survived and hatched with no ill effects. Further, that the fry learn to   survive in adversity, even when combined at birth with other species!

breeding the giant danil with Dr Thomas R. Reich


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Posted in breading Aquarium Fish, Egg Laying Aquarium Fish, Uncategorized

Marimo balls

Marimo BallsMarimo Balls; the Myths and Facts

We were asked a question that needs to be answered in more than one line.  When we have such a question I like to make it into a blog, and let everyone share in the answer.


From: Lynda Pohlmann How are Marimo Balls, are they effective in a fish tank? Marimo Balls
Subject: moss balls (marimo balls)
Message Body:
How are they effective in a fish tank?




Marimo BallsMario Balls are composed of an algae belonging to the genus Cladophora that is commonly found in aquatic systems growing on rocks or in aggregate form.
In certain environments where centrifugal forces are strong, the algae is rolled into balls, which is where we get Marimo balls.
They provide a surface for biofilm grazing as well as limited denitrification.

Common myths regarding Marimo balls include:
They clean the water
As an algae, Marimo Balls utilize Nitrates and other nutrients from the water column, but since they are relatively slow growers, they do not provide substantial denitrification. They will not prevent water changes- Nothing does. They do accumulate debris, so remove occasionally and rinse by squeezing repeatedly in clean water until the sediment is removed. 

They prevent algae
Marimo Balls are an algae! They can provide competition for other algae, but that’s as far as that myth can be stretched

-Marimo Balls reproduce by popping off smaller, baby Marimos. 
Marimo Balls do not. They are simply a ball of algae that only reproduces by growing more strands within the ball. If you want to make new Marimo, you must split the parent ball and roll Marimo Ballsindividual balls. A powerhead in a bucket helps build the ball shape by providing that centrifugal force.

Retail workers come up with some pretty inventive ideas regarding Marimo Balls, but the truth is simple. They are neat little things that have substantial meaning in Asian culture.





Marimo Balls

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Posted in aquarium plants, Questions and Answers