Corematodus

Genus Overview: Corematodus

The genus Corematodus represents one of the most astonishing examples of evolutionary specialization and camouflage in Lake Malawi. Known to biologists as obligate lepidophages (scale-eaters), these rare and unusual cichlids survive entirely by mimicking other fish species to graze on their scales and fin membranes.

Aggressive Mimicry & The Rasping Jaw

The name Corematodus means "sweeper tooth," referencing the highly unique, brush-like arrangement of their teeth. They have evolved a brilliant hunting tactic known as aggressive mimicry. For example, Corematodus taeniatus has evolved a deep, oval body shape, gray-green colouration, and dark vertical bars that perfectly mimic the native Oreochromis (Chambo) tilapia.

By looking identical to their targets, a Corematodus can seamlessly swim right into a peaceful school of feeding Chambo without raising any alarm. Once inside the school, the predator slips up behind a target fish, opens its mouth, and sweeps its densely packed, raspy teeth across the victim's tail fin or flank, safely stripping away a mouthful of nutritious scales and mucus before swimming off.

Valid Species Directory

There are only two valid species natively catalogued within the Corematodus group:

• Corematodus shiranus Boulenger, 1897 – The type species of the genus, specializing in scale-eating along the broader sandy shores.
• Corematodus taeniatus Trewavas, 1935 – Famous for perfectly mimicking Oreochromis species to infiltrate their schools.

Aquarium Considerations

Due to their highly specialized wild feeding requirements, Corematodus species are exceptionally rare in the home aquarium and are primarily studied in laboratories or biotope institutions. In captivity, they can eventually be transitioned to high-protein frozen foods and fresh seafood mixes. However, they retain their wild instincts and must never be housed with slow-moving, peaceful cichlids, as they will relentlessly rasp away at their scales, leaving them vulnerable to fatal skin infections.