Molly or sometimes called Mollies is a type of fish which can withstand tropical freshwater condition to brackish medium salinity water. They are often confused to be similar to platies and swordtails group of fish but however, the mollies are very much different as they belong to other genus and they will not interbreed with those two although chasing and courting activities are commonly seen. In fact, mollies are often kept in the same tank together with the platies and swordtails without any trouble arising and most of the time, all of them will get along well.
There are different variants of the fish which is a result of extensive cross-breeding program done by hobbyist and fish breeders. Sometimes due to the aggressive breeding techniques matching them with other sub-species, most hybrid mollies don’t even look like one anymore and it can be quite difficult to identify them. Mollies in general are black in color but there are variants which are grayish green to yellow and there is even albino type produced albeit very rare. There are even some with the dorsal that projects like a sailfin although the native molly which you often find has the dorsal fin which is only very short and thin. Nowadays, you can also find a new breed called the “balloon mollies” which has a rounded belly which I believe is part of a selective breeding done by fish breeders.



Introducing mollies to an established community aquarium can be a tricky and often complicated thing to do. There are different results; some desired, some undesired that is often seen soon after this new fish is added to the display aquarium. Based on my own experience, some mollies especially the male will end up chasing every single fish larger than its size than it could find while some female mollies will instead nip and harass some smaller sized species such as neon tetra and pencilfish. Most of the time, they will get along well with the others but one important thing noted here is that the molly fish should be given ample space to swim around or else overcrowding and competition for foods will turn them into an aggressive and annoying lot.
Breeding Mollies
Molly just like the other livebearer fish which delivers free swimming baby fish also has a gonopodium to insert to the female specimen and the courting affair is usually interesting to watch as the male flaps open and expand its dorsal fin to get the attention of the other fish. The mollies however, do not make good parents as they will eat their own baby fish, and thus once the female delivers the fry, quickly remove it to another tank away from its offspring. To ensure high success rate on getting more fry, you can consider using a breeding box/net or having live plants in the tank so that the baby fish can hide once they are dropped from their mother.
Breeding Mollies
Molly just like the other livebearer fish which delivers free swimming baby fish also has a gonopodium to insert to the female specimen and the courting affair is usually interesting to watch as the male flaps open and expand its dorsal fin to get the attention of the other fish. The mollies however, do not make good parents as they will eat their own baby fish, and thus once the female delivers the fry, quickly remove it to another tank away from its offspring. To ensure high success rate on getting more fry, you can consider using a breeding box/net or having live plants in the tank so that the baby fish can hide once they are dropped from their mother.