Characins
The characins may usually be recognized by the possession of an adipose fin, which is located on the back between the dorsal and caudal fins. Breeding of all the characins is quite similar, with a few exceptions (when you have bred one you can usually breed them all). There are several very important points to follow when breeding that apply to all the characins.
1. Remove parents after spawning.
2. Feed plenty of daphnia during the spawning process.
3. Keep temperature at about 800 F.
4. Have tank more or less filled with Nitella.
5. Have plenty of infusoria and brine shrimp handy for the young fry.
6. Have no snails in tank with egglayers. Snails eat the eggs.
For the sake of clarity, let us select one characin to be
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representative of the whole family and discuss its breeding habits carefully.
Of all the characins, the most beautiful and difficult to breed are the three "neon" tetras called Paracheirodon. P. axelrodi is the cardinal tetra; P. innesi is the neon tetra; and P. simulans is a rarely imported fish called the false neon.
The longest a neon will grow is 1 1/2 inches, about the size of a large male guppy but much more colorful than the guppy could ever be expected to be. Even if breeding is difficult, neons deserve a place of honor in every community tank because of their unique beauty. They are rather peaceful and very active, always swimming about at high speeds. (This speed decreases slightly when the fish is preparing to spawn, which is one way you may be able to predict to some extent when the female will be ready to drop eggs.)
The breeding of neons requires complete understanding of the general characteristics of the fish. A long, low, 20-gallon tank should be filled with 15 gallons of water (about three-fourths full). Leaving the center free, the bottom should be lined with an abundance of sterilized dense foliage, Nitella being the best. The sides of the tank should also be spread with this Nitella to a thickness of about 2 inches. Have no sand on the bottom of the tank, but do have a few pieces of old log or twigs in the open center portion. Arrange the twigs so there is a maximum area of undersurface free for the young to attach themselves.
The water that is placed in the tank must be specially prepared; the entire success of breeding depends upon the preparation of this water. The primary concern is to have the water bacteria-free. The best water to use is distilled water that has been thoroughly aerated. The aeration apparatus must be sterilized by boiling for twenty minutes before insertion into the tank. Remember to keep everything that goes into the tank sterile. The plants (Nitella) must be sterilized by a thorough treatment with salt and potassium permanganate. The tank itself should be sterilized by soaking for 48 hours with a very concentrated solution of salt and potassium permanganate. The twigs may be sterilized by boiling in water for 20 minutes. The glass cover plate for the tank must also be sterilized and can be placed in the tank with the sterilizing solution. Allow the glass to dry in the air; if the solution was concentrated enough, there will be a salt deposit left on the glass plate when it has been dried. Next, drain the water out of the tank and refill it with the sterile water (boiled for 20 minutes, then cooled); then aerate it for 24 hours. Add enough peat moss boiled water to have a pH of less than 6.
The optimum temperature for breeding is 78° F. The best way to approach this temperature is with a thermostatically controlled heater that has a pilot light that shows when the heater is working. Sterilize this heater by boiling the part of the heater that will be submerged in the water. Steam the top or wash it with alcohol (after unplugging it of course).
When you have selected a very heavy female—she is easily recognized by her roundness in comparison with the slim male—she may be placed for a minute in a 5% solution of salt and potassium permanganate. If you use a net that has been used for other purposes, make sure it has been sterilized before using it to remove the female from the salt solution. Then put her in the tank when the temperature is about 74° F. (of course, the water in the tank from which she has been taken should be the same temperature).
Next, select the male and place him in a weaker solution of salt (2%) and gradually raise the temperature in
this solution to 78° F. At the same time, raise the temperature of the water in the breeding tank to 78° F. and place the male with the female. Then cover the entire tank with a large towel or sheet; this ensures a minimum amount of light and a minimum fluctuation of temperature.
The fish will need some sort of live or freeze-dried food, the best undoubtedly being grown brine shrimp. These brine shrimp are to be raised in a very strong salt solution. If you use a large-mouthed eye dropper, it will be easy to regulate the amount of food you drop in. Care must be taken to feed them enough to satisfy their hunger, but not to feed them more than they will eat. Spawning will take place after a few days when the male chases the female into the vegetation. The eggs are dropped at random while the female swims through the dense foliage; fertilization is haphazard.
As soon as spawning is completed—if the female is very heavy it should not take more than 48 hours—remove the female. The female should be removed before the male, as she is the one that will eat the eggs; the male tries to protect the eggs by constantly chasing the female from them. The eggs are very small and practically colorless. They will hatch out in 36 hours and may be seen clinging to the twigs in the water. The young do not resemble anything at all. They are small and colorless, taking upward of four weeks before they show color. They should be fed on as pure a culture of infusoria, preferably rotifers, as can be prepared; when four weeks old, they will take brine shrimp.
The pH of the water should be kept as close to 6.0 as possible.
The neons may have been an unfortunate selection to illustrate breeding generalities, but if anyone can reproduce them, he can breed any fish. In general, all characins may he bred the same way, with the omission of the sterilization processes.
