Birds do it. Bees do it. And, yes, fish do it too.
But when fish are in an aquarium, it’s up to their owner to make sure they’re in the mood – and to make sure their progeny, or fry, are healthy.
As with other animals, good health begins with healthy parents and continues with proper environment, feeding and a good understanding of the needs of a particular species.
The Right Environment for Breeding
Bringing Up Baby
When everything’s done just right, the fry (newly hatched fish) will follow. Keeping them alive is another story.
Fish fry are often food for other fish. And some fish eat their own young. To keep the little ones safe, relocate the adults to another tank after they’ve laid their eggs or released their fry.
There are, however, some notable exceptions. For example, the anabantoids or labyrinth fish – whose members include the gouramis, fighting fish and paradise fish – protect their eggs in floating bubble nests built by the males. The males guard these eggs against all would-be intruders, including the mothers. Once the eggs have hatched, the male’s job is done and he’s off to spawn again.
Creating a Good Home
Because of their immaturity and size, fry placed in tanks with poorly filtered water or poor lighting are less likely to survive. Their immature immune systems make them very susceptible to bacterial, fungal, parasitic and viral diseases. Here’s what you should do:
Many fish hatch as larvae with an attached yolk sac, which provides nutrition until the larvae are capable of feeding on their own. After that, baby fish must eat at least four to six times a day because they have very high metabolism and lack fully developed digestive systems.
Fry like their food live. Brine shrimp nauplii used to be one of the most common fry feeds, but it is increasingly expensive. Other small live foods include daphnia and microworms, available from some aquaculture-supply companies as well as through hobbyists advertising in trade magazines.
Infusorian, which is essentially a plankton cocktail, is another common first food. These cultures are often found growing in and around aged sponge filters.
Commercially prepared fry foods can be used for some species.
After the first few weeks, most fry can be weaned off live foods and on to dry, prepared diets. Once this happens, the hard part’s over. But some fish, like cichlids, get more aggressive as they get larger and if they don’t get more space – other fish could become lunch.