Breeding and Rearing Live-bearing Species of Fish

Live-bearing species of fish like guppies and swordtails are notorious for breeding in the community tank. If you want to breed these fish on purpose, however, there are a few tips you might want to know.

 If you have a community tank stocked with guppies, swordtails or other live-bearers you should not be surprised to find baby fish swimming around at some point. Live-bearing species of fish are known for reproducing in the community tank with little to no effort on the part of the aquarium hobbyist. Unlike many species of fish which lay eggs, live-bearing species of freshwater fish produce fully-formed fry. These species may reproduce as often as once every few weeks, but they generally produce fewer fry than egg-laying species of fish. If you are interested in trying your hand at breeding freshwater aquarium fish, you may want to start with live-bearing fish. To get started with breeding live-bearing species of fish, you should first learn the basics about what type of fish belong to this group, how to prepare the fish for breeding and how to care for the fry once they do.

Types of Live-Bearing Fish

There are a variety of different species of live-bearing freshwater fish and most of them are fairly hardy in the home aquarium. One of the most well-known species of live-bearing freshwater fish is the guppy. Guppies are known for their long fins and bright colors – they are also known for reproducing frequently and without any encouragement from the aquarium hobbyist. Other popular types of live-bearing species of fish are swordtails, mollies and platies. These fish come in a variety of colors and patterns and, for the most part, they are easy to care for and easy to breed. Swordtails are easy to sex because the males of the species develop a long, sword-like extension of the caudal fin. Mollies and platies are great community fish and, like swordtails and guppies, are peaceful by nature.

Conditioning Fish for Breeding

In order to prepare your fish for breeding you will need to feed them a variety of live food, frozen food and freeze-dried foods. Feed your fish several times a day with different types of food to ensure that all of their nutritional needs are met. If you do not feed your fish a healthy diet, they may be less likely to spawn and they may not produce healthy fry. For the best results, male and female fish should be conditioned in separate aquariums and then joined together when they are ready to reproduce. When the fish appear to be in good health and coloration, they may be ready to mate – if the fish have been properly conditioned, they will likely mate quickly after being introduced into the same tank. To increase the chances of spawning, you might try raising the temperature in the breeding tank a few degrees. It may also help to keep a ratio of 1 male to 2 or 3 females in the breeding tank to reduce aggression between males of the same species. Once the fish have mated, watch the females for the telltale sign of pregnancy – the development of a dark “gravid” spot on the belly. When this spot becomes very dark, almost black, it is a sign that the fish will soon give birth.

Raising the Fry

After your fish have spawned, it is important that you remove the adult fish from the tank. Many species of aquarium fish, particularly live-bearing species, have a tendency to eat their own fry. To prevent this from happening, you should remove the adults from the tank and raise the fry on their own. Though the fry of live-bearing species are generally larger than those of egg-laying species when they become free swimming, they will still be too small to accept flake foods. The best food for young fry is infusoria – you can use an eyedropper to release the infusoria directly into the tank in the midst of the fry. In order for your fry to grow into healthy adult fish it is important to feed them often while they are young – the more you feed your fry, the more quickly they will grow.

As your fry mature, you must perform routine maintenance tasks to keep the tank clean. After the fry are two weeks old, begin to perform weekly water changes of up to 25% of the tank volume. When performing your water changes, use a piece of airline tubing to siphon dirty water and accumulated organic waste from the bottom of your tank, taking care not to suck up any of the fry. As the fry grow, you can begin to feed them larger foods like daphnia, newly hatched brine shrimp and finely crushed flake foods. When your fry become large enough that they will not be eaten by other fish, you can consider adding them to your community tank to finish raising them.