Latin name

Poecilia sphenops

Other name

Mexican molly or simply the molly.

Identification

The Black Molly has an elongated body. Females tend to be more rounded in appearance. The head is pointed. The black-coloured form, the so-called Black Molly, was bred in 1909 and has since become widely used in aquaristics. This variety differs from the wild type in that it is more sensitive and has a shorter lifespan.

Features of fish fins

These fish have a high dorsal fin. Their other fins are rounded and compact.

Fish colouring

This species has many local forms with different colouration. The body colour is usually bluish-grey to brownish-olive. Several longitudinal rows of orange dots and blue-green shiny spots run along the lateral sides of the body. The pectoral and pelvic fins are usually colourless, while the anal fin is orange. Black spots are often visible on the dorsal fin, as well as an orange edge with a black border.

Distribution

They inhabit fresh and brackish waters from Texas to Colombia and Venezuela.

Habitat

The comfortable water temperature for a black molly is between 22 and 28 °C.

Size

Males of this species of fish reach a length of 4 to 6 cm. Females are much larger, growing to between 6 and 10 cm.

Behavior

This is a very peaceful species. They are active fish that prefer the upper and middle layers of water. They jump a lot, so a cover for the aquarium is essential.

Food and feeding habits

The species feeds on small crustaceans, insects, other invertebrates and plant matter.

Reproduction

It reproduces several times a year. After a gestation period of 26–35 days, 28–80 fry, ranging in size from 6–8 mm, appear. If there is a sufficient range of food available, the parents will not chase their offspring.

Aquarium conditions

The temperature should be between +24 and +28 degrees, the acidity should be around pH 7-8.5 and the hardness should be 10-25 dGH. These fish look stunning against a backdrop of live grass.