Opsaridium microlepis

Opsaridium microlepis, the Small-scale Sand Cyprinid, is native to the rivers and streams flowing into Lake Malawi and associated drainage systems in East Africa. Unlike the typical Malawi cichlid, it is a streamlined, open-water cyprinid with fine silver scaling and a distinctly torpedo-shaped body optimised for fast swimming in clear, flowing water.

In the aquarium it requires a large, well-oxygenated setup and is best kept in a group of four or more individuals of its own species. It is a predatory fish by nature and should not be housed with small species. The harder, more alkaline water of the Malawi region suits it well, distinguishing it from the soft-water danionids more commonly encountered in the hobby.

Opsaridium microlepis represents an unusual and rarely kept combination of danionid biology with East African hard-water conditions. It appeals particularly to aquarists who maintain large Malawi cichlid displays and want an active, schooling mid-water species as a complement.

Water: Temperature 22–26°C, pH 7.0–8.5, GH 10–20; hard alkaline water preferred reflecting East African lake tributaries. Tank: Minimum 400 L; long open tank; strong filtration; sand or gravel substrate; robust décor. Feeding: Large pellets, krill, lance fish, and earthworms; predatory appetite requires protein-rich diet. Breeding: Not documented in captivity; specialist breeding facilities required. Compatibility: Predatory toward small fish; suitable with large Malawi cichlids or other robust East African species of comparable size.