蓝纹黑丽鱼

Overview

Melanochromis cyaneorhabdos is a Malawian mbuna whose sexes share similar colors. Often traded under the older name “maingano”, it remains aggressive and territorial. The fact that both sexes are blue should not obscure the importance of sex ratio and male pursuit.

Distribution & habitat

Endemic to Lake Malawi, it is known from one locality on Likoma Island's northeastern shore between Mbako and Membe. Rocky shorelines are its habitat.

Aquarium setup

A tank around 90 × 45 × 38 cm provides a reference. Arrange extensive rockwork into caves with small open gaps, preferably over sand. Maintain strong oxygenation and sufficient shelter for pursued fish to escape direct view.

Diet & feeding

Most foods are accepted, but plant ingredients such as spirulina flakes and blanched spinach should form a large share. Supplement with live and frozen foods rather than allowing acceptance of animal fare to displace the plant component.

Behaviour & compatibility

Avoid gentle peacocks and utaka; selected mbuna are more appropriate. Conspecific intolerance makes several females per male useful for spreading harassment. Denser communities are sometimes used to distribute aggression and weaken fixed territories, but require sufficient space, filtration and oxygen. Exclude other Melanochromis from breeding arrangements to avoid hybridization.

Sexual dimorphism

External sexing is difficult because colors are similar. Males may be only slightly larger.

Breeding

Females mouthbrood, and breeding is generally relatively straightforward. A dedicated aquarium around 90 cm long can hold one male with at least three females, with flat stones and open bottom. Approximately pH 8.2–8.5 and 25–26.5 °C are references, with live, frozen and plant foods for conditioning.

The male cleans a site and displays. The female immediately collects the eggs after laying and receives sperm while responding to anal-fin egg spots. She may brood for three to four weeks without eating, developing a swollen mouth. Stress can cause premature release or consumption of the clutch, and prolonged absence can alter social rank. Limit unnecessary relocation unless harassment requires it. Released fry accept brine-shrimp nauplii.

Notes

This fish is sometimes incorrectly sold as “electric blue johanni”. Dominant males are more blue overall than those of Melanochromis johanni, which show more black. Similar trade names do not establish identical species, particularly when deciding which fish to breed together.