Best kept in a biotype tank with other medium-sized Lake Tanganyika Cichlids; best kept in pairs or colonies.
The Calvus is endemic to Lake Tanganyika in eastern Africa where it can be found living among the rocks along the shore of the lake. These fish exist in several morphological varieties including black, yellow, white and a black and white striped variant. This species typically exhibits a laterally compressed body which allows it to squeeze into crevices in rocks in search of prey. This body shape also gives the fish an advantage over predators because it makes it easy to spot head-on. Calvus have thick, armor-like scales which can be used as weapons against predators.
These fish are sensitive to changes in water chemistry and, though some tank-bred specimens are hardier than wild-caught specimens, these fish are not recommended for beginning aquarium hobbyists. Calvus should be kept in large tanks decorated with plenty of rocks to create caves and the lighting should be kept fairly dim. Black Calvus will display their best coloration over dark substrates and White Calvus show best over light substrate.
Calvus are predatory fish, feeding on eggs, fry and small fish in the wild. In the home aquarium, these fish should be offered meat-based live and frozen foods. While some tank-bred specimens may accept prepared foods, most wild-caught specimens will not. Feed a varied diet consisting of brine shrimp, bloodworms, and mysis shrimp. Once adjusted to your aquarium they will readily accept most prepared carnivore Cichlid pellets. Feeding live feeder fish isn't recommended since it opens the door to introducing disease into the aquarium. If you choose to feed live feeders then it's best to simply raise your own guppies for this purpose.
These fish have been known to spawn in the community tank but, in order to raise the most fry, a separate breeding tank is recommended. Calvus are substrate spawners and they typically lay their eggs in the substrate inside caves. To encourage breeding behavior, the breeding tank should be kept at a pH between 8.0 and 8.5 and at a temperature between 77 and 80 degrees Fahrenheit. After spawning has occurred, the female will guard the eggs while the male tends the nest. The eggs typically hatch in about 2 days and the fry becoming free swimming after another 8 to 10.