珍珠亮丽鲷 · Calvus Cichlid

Overview

Altolamprologus calvus is a strongly compressed predator adapted to exploring rock crevices. Usually shy and relatively tolerant of fish too large to swallow, it nevertheless hunts eggs, fry and small fishes. Stable hard, alkaline water, plentiful caves and appropriate companions are essential considerations.

Distribution & habitat

Endemic to Lake Tanganyika, it occupies rocky areas around the shores and islands. Its narrow shape allows access to cracks and also makes it difficult to see head-on, helping it evade predators and approach prey.

Aquarium setup

Arrange extensive secure rockwork to provide caves and narrow retreats. Subdued lighting encourages more visible activity, and dark substrate particularly enhances black forms. Newly imported wild fish are sensitive to changes in water chemistry. Captive-bred individuals are generally hardier, but sudden chemical or temperature changes should still be avoided.

Diet & feeding

Natural prey includes eggs, fry and small fish. Meaty live and frozen foods are usually accepted readily, whereas dry foods are often refused. Confirm that each individual actually eats rather than assuming that added pellets have supplied a meal.

Behaviour & compatibility

The species is territorial but generally peaceful toward fish it cannot swallow. Avoid aggressive or excessively active companions. Suitable Tanganyikan cichlids and appropriate lake-native catfishes are possible choices. Pairs can be maintained, and colonies are possible with adequate room. Keep different locality forms apart to prevent hybridization.

Sexual dimorphism

Males become larger and develop longer fins than females.

Breeding

Eggs are laid on a surface inside a narrow cave. Juveniles can be raised together to obtain a natural pair, although this may take about two years; one male with three or four females is another breeding arrangement. Provide rock cavities, pots or shells, hard alkaline water around pH 8.0–8.5 and 25–26.5 °C, and varied live and frozen foods for conditioning.

The female chooses a cavity only she can enter. After she lays, the male releases sperm outside and both fan it toward the eggs. A brood may contain around 200 eggs. The female tends them while the male guards outside. Hatching takes about two days, followed by another eight to ten before free swimming. Remove the male after hatching because he may eat swimming fry; the female usually does not. Fry can start on brine-shrimp nauplii and microworms. Growth is slow, and size grading is needed as larger youngsters may eat smaller ones.

Notes

Thick, serrated scales provide defensive armor when turned toward an attacker. The bare patch between the eyes explains the species name; it does not make the fish generally scaleless. Its snout and overall form are more elongated than those of Altolamprologus compressiceps, although identification should consider the full set of features.