For fish fanatics, there is nothing more satisfying than creating the perfect environment for your fish to propagate. While most fish hatch from eggs there are a number of species that bear live young. These fish are described as livebearing and they include popular aquarium fish such as guppies, swordtails and mollies.
Before you make the decision to bred livebearing fish though, it is important to ensure that you can on-sell or house the young fry. Your aquarium fish should never be dumped into drains and rivers. Livebearers, like guppies, are prolific breeders and in as little as four weeks a female guppy can give birth to as many as thirty young. Non-indigenous livebearing fish, such as the One Spot livebearer, have caused serious problems in Australian waterways and compete with native fish for territory and food.
Responsible fish ownership can be very rewarding. Livebearers give the enthusiast the opportunity to branch out and try their hand at genetics by breeding fish for specific colours or fin formations. Guppies are a popular choice with those new to fish breeding. These colourful and active fish are very robust. Once your fish have successfully bred, it’s important to separate the parents from the fry – adult fish have no maternal or paternal instincts and will happily eat their young. Although it is one way of keeping your live stock in control!
Unlike fry born from eggs, livebearers can eat immediately after being born and thrive on commercially available fry food. The fry are active and grow rapidly and require feeding three times a day.
Mollies are another popular livebearing fish for the aquarists. The males can be quite aggressive so it is advisable to keep one male with several females. Mollies are quite territorial and so don’t tolerate other fish species in the tank with them. They will constantly annoy larger fish by nipping their fins and tails. Mollies are found in intertidal areas where freshwater rivers flow into the sea so they do best in slightly alkaline water. If you do have other species in the tank with them make sure they can tolerate brackish water and are large enough to intimidate the pestering molly.
Swordtails are another popular aquarium livebearing fish. These colourful fish originate from Mexico. The males and females display strong colours, they are usual bi-coloured with a solid body colour such as red or green and fins and tails in a contrasting colour such as black. The male is easily identified by the sword like appendage under his tail. Like other livebearers the males tend to harass the female so it is important to have at least three females to every male. Swordtails will happily share with other species and make an interesting and colourful addition to your tank.
While livebearers like open water to swim in it is useful to provide plants and rocks as part of your aquarium decoration. This will provide hiding places for the females and refuges for other fish in your tank.