The Black Molly prefers a tank of at least 30 gallons with plenty of strong plants such as Java Fern, Sagittaria, Vallisneria, and Anubias. They require a good filtration system because of their hearty appetites and resulting waste products. The Black Molly is well suited for the community tank because of its peaceful nature, and is compatible with other peaceful, large fish that can withstand similar water conditions.
The pointed anal fin and much larger dorsal fin on the male, and the rounded anal fin and pregnancy spot on the female differentiate the two. The Black Molly is a livebearer that requires a spawning box in a 25 gallon, or larger breeding tank. The aquarium should be planted as densely as possible or have a thick algae mat. Having a group of floating plants in the corner of the aquarium will promote rearing outside of the breeding tank. Every 60-70 days the female give birth to 10-60 young that are already approximately one-half inch long.
The Black Molly is omnivorous and that prefers both meaty foods as well as algae. Provide these fish with an algae-based flake food, as well as freeze-dried bloodworms, tubifex, and brine shrimp.