Mollies (Poecilia sphenops) are one of the most common aquarium fishes. Because of their growth and prolific breeding nature, they are also considered one of the most sought after feeder fish (used as live feed for carnivores). They like to live in groups, often happy with more than 4 pairs. Like any tropical fish they like temperatures around 80 degree F (27 degree C). Neutral to slightly alkaline pH (up to 8) are ideal. Some aquarists will recommend you to add a teaspoon of salt per gallon of water, but if you have a water that has hardness of potable quality, that should work well for mollies. Like other live bearers, mollies breed readily in home aquaria without much difficulty. In fact most female mollies are pregnant most of the time! Here is a quick guide if you are wondering about basics of molly breeding.
Procuring breeding pairs:
Since mollies are live bearers (directly give birth to young ones), it is easy to select your breeding pair. If you go an aquarium store, you most likely will find pregnant mollies swimming around. Rounded abdomen is the most evident sign of a bearing molly.
How to tell if the molly is male or a female:
With babies in the belly, females look bulkier in the abdomen than males. Females are generally larger than males. Males have something called gonopodium in the anal fin. Gonopodium is a tube-like copulatory organ that inserts sperms into the female’s body to fertilize eggs. So when you see males chasing females with anal fin bent in the opposite direction, you know they are bound by nature’s course
Water pH of 7.0 – 8.5 are considered good for mollies but we recommend pH up to 8.0 for breeding. Once you procure your breeding pair, let them stay together for a couple of weeks. If you are procuring pregnant females, you can isolate her in a 10-15 gallon tank.
Provide lots of hiding for the babies. Live plants are the best bet. Lots of plants planted close to each other make good hide for babies. Live plants also give mother and babies enough algae in an aged tank. This serves as natural food for them. So aging tank for few weeks to months is also beneficial in more than one ways. You can also use commercial fry-traps for this purpose. Special plants called baby-hide are also available at your pet-store. Mother might eat the babies right after the breeding, so if the babies do not have enough cover, they might lose life to the mother who gave them one!
Female will give birth to young ones by twitching her body. Young ones start swimming right away. They start to feed upon algae right away. You should remove the mother from the tank because she might try to eat babies if not enough hiding is available for babies.
Caring for the babies:
Since babies start feeding right away (they do not have yolk sac as in egg-laying fishes), it is important to provide them sufficient food. Live feed like newly hatched brine-shrimp, or daphnia etc make good feed. But well grown algae on the plants and aquarium surfaces is enough for the babies. They also can eat any pelleted feed provided the pieces can fit into their mouth.
Hope you start seeing baby mollies soon!