Abactochromis labrosus (Trewavas 1935)

This species is distinguished from all other mbuna genera by the following characters: strongly hypertrophied , papillose, medially lobate lips; large head at least 40% SL in > 5 cm SL individuals; premaxillary pedicel (ascending process) >35% HL. Other non-mbuna haplochromine species endemic to Lake Malawi resemble this species in having enlarged and often lobate lips, but all can be distinguished as follows: Placidochromis milomo with total vertebrae 30-31 (vs. 28-29 in Abactochromis), segmented anal-fin rays 9-10 (vs. 7-8), broad, black vertical bars below the dorsal-fin base 4 (vs. 6-7 narrow subdorsal bars when distinct), reaches at least 19 cm SL (vs. ca. 12 cm); Otopharynx pachycheilus with longer pectoral fin 38-44% SL (vs. 19-27), shorter premaxillary pedicel 24-35% HL (vs. 36-46), color pattern of three lateral spots (vs. vertical bars with no lateral spots), depth range of 78-135 m (vs. 0-30 m); Cheilochromis euchilus total vertebrae 30-31, head and jaws not laterally compressed (vs. distinctly compressed), 2-3- horizontal stripes (vs. narrow bars with no horizontal stripes); Chilotilapia rhoadesii total vertebrae 31, thickened lips with no median lobes (vs. strongly lobate medially), adult teeth for crushing gastropod molluscs - robust with crowns shaped like grains of wheat, blunt, recurved and grooved on the outer surface (vs. oral dentition not similarly specialized), head and jaws not laterally compressed (vs. compressed), 2-3 horizontal stripes (vs. narrow bars with no horizontal stripes); Eclectochromis spp. with total vertebrae 30, segmented dorsal-fin rays 10-11 (vs. 7-9), thickened lips with no median lobes, some submolariform posteromedian pharyngeal teeth (vs. posteromedian teeth slightly enlarged by their crowns laterally compressed), color pattern of vertical bars alternating with dark spots along dorsum (vs. bars only); Lichnochromis acuticeps total vertebrae 32, thickened lips with no median lobes, with oblique stripe from nape to base of caudal fin (vs. no oblique stripe) (Ref. 85491).

Dorsal spines (total): 1517; Analspines: 3; Vertebrae: 28 - 29

Found over rocky substrate (Ref. 6307).

aquarium: commercial

Abactochromis is a monotypic genus of cichlid fish containing the single species Abactochromis labrosus (formerly known as Melanochromis labrosus). The genus name combines the Latin for "driven away from" ("ab" - away from, "actus" - driven) with the commonly used haplochromine name "chromis". The name encompasses both the origin of the genus (the species was "banished" from the genus Melanochromis) and the fish's solitary, wandering behaviour (as if it had been driven away from the other cichlids).

A. labrosus is native to Lake Malawi. The largest known wild specimen (shown in the photo at right) had a standard length (without caudal fin) of 119 mm (4.7 in).