Care guide · Freshwater · fish

Calvus cichlid care

Altolamprologus calvus

Calvus; photo: Melanochromis via Wikimedia Commons, public domain (PD-self). Photo: Melanochromis · Source · Public domain, PD-self (released by author Melanochromis)Resized and compressed; no cropping or colour changes.

The calvus cichlid (Altolamprologus calvus) is a slow-stalking Lake Tanganyika cichlid with a strongly compressed body. It slips into narrow rock crevices to hunt small crustaceans, eggs and young fish. It is therefore unsuitable for a tank with ornamental shrimp or small fish. Provide a stable aquarium with rocky cavities and hard, alkaline water. FishBase reports an adult maximum of 13.5 cm total length; AquaInfo gives a minimum length of 80 cm for a pair. A reliable minimum volume in litres has not been established.

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At a glance

Temperature: 24–25 °C
pH: 8.0–9.0
GH: 9–19 °dGH
Aquarium length: At least 80 cm
Adult size: Up to 13.5 cm
Group size: At least 2 individuals
Temperament: Predator

About this species

Altolamprologus calvus was described by Max Poll in 1978. The accepted combination is Altolamprologus calvus; Lamprologus calvus is the original combination. It lives in Lake Tanganyika and belongs to the Cichlidae. FishBase records up to 13.5 cm total length, while the Seriously Fish genus profile gives 13.8 cm standard length. Standard length excludes the tail fin, so these measurements are not directly comparable. Dark, white and yellow colour forms are geographical variants; do not confuse this species with Altolamprologus compressiceps.

Natural habitat

Calvus is endemic to Lake Tanganyika and occurs mainly in the southwestern part. It lives among rocks and crevices. Its tall, narrow body lets it enter tight gaps and stalk prey. FishBase describes shrimps and other crustaceans as important foods; eggs, fry and small fish are also prey. Its refuge and hunting area are therefore part of the same rocky habitat.

Aquarium and layout

Use firmly secured rocks with narrow cracks and caves. Set the rocks on the tank base before adding sand so digging cannot undermine them. AquaInfo recommends at least 80 cm aquarium length for a pair. This is not a recommendation for a mixed community; tankmates require extra space and clearly separated zones. A safe litre minimum cannot be derived from this length alone. Keep small fish, shrimp and fry out of reach of the calvus. Ensure it can feed without being constantly chased.

Water conditions

Seriously Fish gives 24–27 °C, pH 7.5–9.0 and 8–20 dGH as aquarium guidance. FishBase describes field values of 23–25 °C, pH 8–9 and hardness 9–19 dH. The overlap is 24–25 °C, pH 8–9 and 9–19 dH. These are conservative references, not a guarantee that every fish will thrive at every boundary. FishBase field data is not a complete aquarium manual. Keep water stable, test replacement water and avoid abrupt changes. GH and KH are different measurements.

Behaviour and group size

Calvus is a cautious predator that often waits quietly among rocks before striking. It may eat small fish, fry, eggs and ornamental shrimp. Do not keep it with animals small enough to swallow, or in a shrimp-focused aquarium. When considering other Tanganyika cichlids, assess adult size, feeding competition and territories individually. The reviewed sources do not establish universally safe tankmates or a standard group size. Provide calm retreats and check that the fish is actually getting food.

Feeding

In the wild, calvus feeds mainly on shrimps and other crustaceans and also stalks eggs, fry and small fish. Offer varied meaty foods, such as suitable live or frozen prey. Treat dry food only as a supplement after confirming that the individual accepts it; the reviewed species sources do not confirm a specific central product variant. Feed small portions the shy fish can take calmly and remove leftovers.

Breeding

FishBase reports that the female guards the eggs and records clutches of about 200. The species uses narrow rock crevices and caves, so provide stable rockwork with suitable openings. The reviewed sources do not establish a sufficiently reliable universal incubation time or minimum breeding tank size. Small fry may be eaten by adults or other tankmates. Protect a brood only if you intend to rear it and can provide a suitable separate grow-out space.

Sources & review

This care guide draws on several specialist sources and was last checked on 17 October 2026.

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