黑花鮰 · Short-finned Molly/Black Molly

Overview

The familiar black molly is one of many ornamental forms associated with Poecilia sphenops. Its peaceful nature and frequent recommendation to beginners do not remove its need for mineral-rich, nonacidic water.

Distribution & habitat

The native range extends northward from Venezuela and Colombia to Mexico, with isolated Caribbean island populations. Introduced or feral fish occur elsewhere, including the United States, Japan, Singapore, and parts of eastern Europe. Far Eastern and Eastern European farms supply most aquarium stock.

Aquarium setup

A tank at least about 90 cm long, preferably planted, is appropriate. Soft or acidic conditions can cause progressive weakness, with shivering movements, clamped fins, or fungal problems among the possible signs. Calcium and magnesium availability matters more than simply adding salt; suitable hard freshwater does not require salt supplementation.

Brackish conditions are also tolerated. Choose a system that suits every occupant rather than changing salinity in an incompatible community.

Diet & feeding

The natural omnivorous diet includes small bottom-dwelling animals and detritus. Aquarium foods are readily accepted, but provide a substantial plant component, such as softened spinach or vegetable flakes.

Behaviour & compatibility

Companions must tolerate the same hard-water conditions. Appropriate rainbowfishes, small cyprinids, and characins are possible choices. Several females per male and dense planted retreats help reduce relentless courtship pressure.

Sexual dimorphism

Males are smaller, more colorful, and equipped with a gonopodium.

Breeding

Suitable water chemistry generally makes breeding easy. Pregnancy lasts around eight weeks and broods can reach approximately 120 young. Adults eat offspring, so use a separate maternity aquarium and return the female after delivery. Small net boxes and traps lack sufficient rearing space.

Newborns are large enough to take Artemia nauplii or finely crushed flakes immediately.

Notes

Black, gold, green, silver, spotted, and lyretail forms are among the ornamental selections. Some have hybrid ancestry involving Poecilia latipinna, and these fishes also interbreed in aquariums, so separate them when preserving stock.

Wild-type resilience has been reduced in some heavily inbred commercial lines, particularly common black forms. Balloon-shaped bodies may cause digestive and swimming-bladder problems and shorten life. Environmental tolerance should not be treated as a reason to expose fish to an unstable new aquarium.