Taxonomy & naming
Otopharynx tetrastigma belongs to the genus Otopharynx, one of the non-mbuna haplochromine lineages recognised during the twentieth-century revision of Lake Malawi's cichlid taxonomy, when the original catch-all genus Haplochromis was progressively split into better-diagnosed genera on the basis of tooth form, jaw structure, and other anatomical characters. Eschmeyer's Catalog of Fishes is the reference for the currently accepted describing authority and date, which is not restated here to avoid an inaccurate citation. The species epithet tetrastigma is transparent Greek — tetra (four) plus stigma (mark, spot, or brand) — describing a four-spot pattern along the body that functions as a field character separating this species from related Otopharynx.
Morphology
This is a moderately deep-bodied, laterally compressed haplochromine on the standard Otopharynx plan. Its defining field character, encoded in the name, is a series of four dark blotches or spots along the flank — a pattern that, unlike the plain barring of many related species, gives a quick and reliable way to identify it in the field or in photographs. Precise published length figures for this species are not confidently known here; genus members typically range from about 4–7 in total length. Sexual dichromatism is expected: females and non-breeding males carry the diagnostic spotted pattern on a duller silvery-grey ground, while breeding males likely intensify in colour, in keeping with the genus.
Habitat
Otopharynx tetrastigma is documented from Kanchedza Island and Thumbi East Island, both part of the tightly clustered island group off Cape Maclear in the southern end of Lake Malawi — an area of clear water, extensive rocky reef, and adjoining sand that has been a focal point of cichlid research and photography since the mid-twentieth century. As with other Otopharynx, the species is expected to occupy the intermediate zone, foraging around isolated rocks and boulders that stand on open sand rather than committing to continuous rock. Water there follows the standard Lake Malawi profile: warm, alkaline, and well-buffered, in the mid-20s Celsius with a pH on the alkaline side of neutral.
Feeding
As a member of the sand/rock-interface guild of Malawi haplochromines, O. tetrastigma is expected to feed as a generalist invertivore, picking small crustaceans, insect larvae, and other invertebrates from crevices and the sediment surface around rocks. No species-specific dietary study is documented here, so this account follows the broader feeding ecology described for Otopharynx as a genus rather than a confirmed study of this particular species.
Mating
Reproduction is expected to follow the polygynous, lek-like pattern typical of Lake Malawi haplochromines: territorial males in breeding colour hold and defend a site on or near the substrate and display to attract females, which move between males rather than pairing with one. No field study of courtship specific to O. tetrastigma is documented here; this account reflects the general pattern shared across the genus and family rather than direct observation of this species.
Breeding
Otopharynx tetrastigma is presumed to be a maternal mouthbrooder, following the near-universal pattern among Lake Malawi haplochromines. After spawning at a male's display site, the female takes the eggs into her mouth and broods them alone through hatching and early development, releasing free-swimming fry after several weeks with no further parental care. Clutch size and exact brooding duration have not been documented for this species specifically; a fish of this general size in the genus would be expected to carry on the order of a few dozen eggs.
In the aquarium
Otopharynx tetrastigma does not have an established presence in the aquarium hobby that is documented here, and specific keeping notes for it are not available. If obtained, husbandry would be expected to follow the standard approach for an intermediate-zone Lake Malawi haplochromine: a spacious tank combining open sand with rock structure, alkaline water buffered into the high 7s to high 8s pH range, and a varied diet built around a quality cichlid pellet supplemented with small invertebrate foods rather than fatty, high-protein fare, which is linked to digestive problems in this group.
Conservation
No confident IUCN Red List status is available for Otopharynx tetrastigma and none is asserted here. As a species tied to the well-studied but heavily visited Cape Maclear island reefs, it would share the general pressures affecting that stretch of shoreline — tourism and boat traffic, ornamental collection, and inshore sedimentation — but no formal population assessment is documented in the sources consulted for this article.