Black Molly

Bred aquarium fish

The wild variety of Poecilia sphenops is often called short-finned molly. In the wild, it mainly lives in brackish water and it has a greyish-green body with an orange pattern on its dorsal and anal fins. From this species, aquarium keepers have bred several different varieties and body shapes. One of the most common varieties is the very popular aquarium fish called Black Molly.

This completely black fish is considered wholly domesticated, i.e. it has been bred and developed by people controlling the selection and keeping the species in aquariums. 

The male dances for the female

A sexually mature male short-finned molly has fin rays in its anal fin that have been modified to function as a reproductive organ, known as a gonopodium. During the breeding season, the male puts on a display and “dances” in front of the female. When spawning, the male fertilises the eggs which the female carries inside her body. After spawning, the female withdraws to a place among the plants and roots. The eggs hatch inside the female and she gives birth to small fry that can already swim.