Cauca molly

Poecilia caucana

FreshwaterBrackishFish

Care at a glance

Temperature: 77–86°F (25–30°C)
pH: 7.0–8.5
Adult size: 2.4 in (6 cm)
Minimum tank: 16 gal (60 L)
Temperament: Peaceful
Social behavior: Social
Swim level: Middle
Difficulty: Easy
Breeding: Easy
Rarity: Very rare
Origin: Panama, Venezuela, Colombia
Family: Poeciliidae

Overview

The Cauca molly is a small, peaceful molly that likes to be in a group, so keep a handful with more females than males. It spends most of its time in the middle of the tank and mixes well with other calm species. Like most mollies it grazes hard on algae and aufwuchs, so give it a flake or pellet with plenty of vegetable content alongside occasional small frozen foods. It thrives in hard, alkaline water and takes well to a little added marine salt, matching the brackish coastal waters it sometimes lives in. A tank of 60 liters or larger works well for a small group.

In the wild

Poecilia caucana ranges through Panama, Colombia and Venezuela, living in warm lowland streams, ditches and coastal lagoons. It moves between fresh and slightly brackish water, so it is used to hard, mineral-rich conditions. Keep it warm, between 25 and 30 C, with a pH from about 7 to 8.5 and firm, alkaline water. A planted tank with open swimming space, gentle flow and good light to grow algae suits it well. A little salt is fine but not essential.

Good to know

The Cauca molly is a true livebearer in the family Poeciliidae and, at around 6 cm, one of the smaller wild mollies. Males are slim and carry a gonopodium, a modified anal fin bent into a mating organ that fertilizes females internally. The larger females then carry the embryos inside the body and give birth to live, free-swimming fry rather than laying eggs. Broods come frequently in warm, hard water, and the species is easy to breed, which is why it turns up now and then in the hobby.

Did you know

Unlike the familiar sailfin mollies, the Cauca molly stays small and keeps a plain silvery body marked with rows of small dark spots, a look closer to a wild guppy than a fancy molly.