Some specimens have enlarged lips, though this condition is thought to be related to specific food choice preferences in their natural habitat as this trait disappears in captivity.

[citation needed] Aquarists who keep cichlids regard red devils as aggressive fish.

This aggressive behavior combined with their razor sharp teeth and powerful jaws means cohabitants should be chosen carefully and the fish should be kept in a large aquarium.

Red devils may be so aggressive that they ram into the glass to get at invaders, break heaters and other aquarium equipment, and will sometimes bite their owners.

However, it was released to the wild and has become an invasive species, especially in the lakes of Java, Sulawesi and Papua.