Calvus Cichlid

Adults grow up to 14 cm in length. Sexual dimorphism is weakly expressed, with males only slightly larger than females. Body coloration varies from gray to dark tones, adorned with dark vertical stripes. One of the most striking characteristics of the species is its laterally compressed body and elongated head. This structure allows the fish to hunt effectively among rocks, penetrating the narrowest crevices.

This species is endemic to Lake Tanganyika, located in Africa, predominantly between Tanzania and the Democratic Republic of Congo. Its natural habitat consists exclusively of rocky shorelines.

This species is territorial and predatory, yet relatively peaceful. It coexists well with other peaceful inhabitants of Lake Tanganyika. It is advisable to avoid housing them with Mbuna cichlids and other aggressive fish, as well as any fish that could become prey for the Calvus. They can be kept in pairs or small groups.

To achieve optimal keeping conditions, a biotope aquarium replicating the natural habitat of Lake Tanganyika is recommended. For a group of Calvus cichlids, the tank volume should be at least 150 liters. Decorations should include rock formations and stone fragments that create crevices and caves. It has been observed that using a dark substrate enhances the fish's coloration, while light substrates can make it duller. Maintaining stable water parameters with appropriate hydrochemical indicators is crucial for successful keeping. A powerful filtration system is essential, as is weekly partial water changes with fresh water. Regular aquarium cleaning also plays a significant role.

Being a predator, this species is carnivorous. In a home aquarium, its diet can include both fresh and frozen meat products. These include fish meat, shrimp, mussels, and other invertebrates such as large bloodworms and Artemia.

During the breeding season, Calvus cichlids form pairs, but this only happens if the fish have grown up together. If one tries to combine adult individuals raised in different conditions, breeding becomes unlikely. These fish can breed in a community tank, but raising offspring there often fails, as they risk becoming prey for other inhabitants or even the males. More favorable conditions are created in a separate spawning tank. During the mating period, the male chooses a crevice or grotto and attracts the female there. The eggs are laid inside the shelter, after which the male, while outside, releases milt, which is then directed by fins towards the eggs for fertilization. The pair guards the clutch alternately. Fry appear after 8–10 days and begin to swim freely after just a couple of days. At this stage, it is advisable to remove the male to avoid him eating his own offspring; females, as a rule, are indifferent to the fry. The young can be fed with Artemia nauplii and small bloodworms. It is important to note that fry grow unevenly. As they mature, smaller individuals should be separated, otherwise they may be eaten.

The main cause of most diseases in Lake Tanganyika cichlids is unsuitable keeping conditions and poor-quality food, which often leads, for example, to African Bloat. At the first symptoms, it is necessary first to check the water parameters and ensure there are no high concentrations of dangerous substances such as ammonia, nitrites, and nitrates. If the readings deviate from the norm, they should be brought into order, and only then should treatment begin. More detailed information on symptoms and treatment methods is available in the “Aquarium Fish Diseases” section.

When choosing Altolamprologus calvus, preference should be given to individuals that show activity and curiosity, but it is important to remember that these fish are naturally cautious and may hide in shelters. A healthy fish should have clean fins without signs of erosion or plaque, clear eyes, and even breathing without rapid gill cover movements. Avoid specimens with sunken bellies, which may indicate emaciation or internal diseases, as well as individuals with visible skin damage, as due to their specific body structure, they are prone to injuries during improper transportation.

Since Calvus are territorial predators, in the store they may show signs of stress, expressed as darkening coloration and the appearance of contrasting stripes on the body. When purchasing, it is recommended to:

• carefully inspect the scales for the absence of spots, ulcers, or white plaque;
• ensure there are no jaw or spinal deformities, which are sometimes found in individuals raised in unsuitable conditions;
• inquire about the keeping conditions and diet, as these fish are sensitive to water quality and the quality of protein feeds.