Taxonomy & naming
Labrochromis teegelaari was described by P. Humphry Greenwood and Cees D. N. Barel in 1978, in the Bulletin of the British Museum (Natural History), from material collected in the southern part of the Mwanza Gulf near Busissi, on the Tanzanian side of Lake Victoria, at a depth of about 2 metres. The holotype (BMNH 1977.1.10.16) and a series of paratypes are held in the Natural History Museum, London. The work was part of the Leiden-based HEST programme (the Haplochromis Ecology Survey Team), a Dutch-British collaboration that, together with Greenwood's revisions, set out to make sense of Lake Victoria's vast and confusing haplochromine flock before it could be properly studied. The species was named for Nico Teegelaar (1926–1976), a Dutch scientific illustrator whose drawings accompanied a number of Barel's papers. Like most Victoria haplochromines the fish was placed in the catch-all genus Haplochromis, but Greenwood (1980) referred it to the small genus Labrochromis, a group of heavy-jawed mollusc-crushers, and recent work (Mahulu & Seehausen 2025) continues to treat it as Labrochromis teegelaari. Because the generic split-up of the Lake Victoria flock remains contentious and inconsistently applied, the broad name Haplochromis is retained here as the heading, with Labrochromis noted as the modern placement.
Morphology
This is a small cichlid: FishBase gives a maximum of about 4 in standard length, and like its relatives it has the deep-bodied, laterally compressed haplochromine build. Its defining feature is internal — the genus Labrochromis is diagnosed by a massive hypertrophy of the pharyngeal mill, the throat jaws being greatly enlarged and armed with broad, blunt molariform teeth for crushing shells. The oral teeth are comparatively modest, moderately stout and slightly recurved. Breeding males carry the bright nuptial dress typical of the flock: a purplish-grey to brownish-grey snout and dorsum, golden-brown on the gill cover and front of the flank, and red flushing across the flanks, chest and belly, set off by the dark egg-dummy spots on the anal fin used in spawning. Females and non-reproductive fish are a plainer silvery to brownish grey, as is the rule among haplochromines, where the showy colour is concentrated in courting males. Sexual dichromatism of this kind is the prominent dimorphism in the group rather than any large difference in size or shape.
Habitat
Labrochromis teegelaari is endemic to Lake Victoria, the great shallow equatorial lake shared by Tanzania, Uganda and Kenya; the type and recorded material come from the Mwanza Gulf in the Tanzanian south of the lake, and the IUCN assessment lists only Tanzania as a range country. It is a fish of relatively sheltered, soft-bottomed habitats — FishBase records it from quiet areas over a mud substrate at depths of roughly 2 to 8 metres. That sub-littoral, soft-sediment zone is exactly where snails and bivalves are abundant, and exactly where the Nile perch upsurge of the 1980s hit the haplochromine community hardest. Lake Victoria water is warm and on the hard, alkaline side for a tropical lake: surface temperatures run roughly 73–81 °F and pH typically sits around 7.2 to 9.0, with the open lake well-buffered and moderately mineralised. No in-situ chemistry specific to this species was published in its description beyond the habitat and depth notes.
Feeding
Labrochromis teegelaari is a molluscivore — a pharyngeal crusher of hard-shelled prey. FishBase records it feeding on bivalves, and the genus Labrochromis to which it belongs is built around exactly this trophic role: the hypertrophied lower pharyngeal bone and its broad molariform teeth form a powerful mill that cracks the shells of snails (such as Melanoides) and small clams, after which the soft tissue is swallowed and the shell fragments rejected. FishBase places it at a trophic level near 3.1, consistent with an invertebrate-eater rather than a piscivore. Mollusc-crushing is one of the classic trophic guilds that the Lake Victoria flock evolved repeatedly, alongside algae-scrapers, insectivores, zooplanktivores, paedophages and fish-eaters; teegelaari is one of the soft-bottom specialists that worked the lake's beds of snails and mussels.
Mating
No courtship account specific to Labrochromis teegelaari was published, so what can be said is drawn from the well-studied biology of the Lake Victoria haplochromine flock, of which it is a typical member. These cichlids are polygynous maternal mouthbrooders in which the sexes separate sharply at breeding time: males develop bright species-specific nuptial colour — in teegelaari the red flanks and golden-brown forebody described from ripening specimens — and display to females, while females remain cryptic. Males of the flock are generally lek- or territory-based, defending a small patch of substrate and courting passing females with lateral displays and quivering, the anal-fin egg-dummies playing a central role in the spawning sequence. Female mate choice on these visual colour signals is the engine that is thought to have driven and maintained the flock's explosive speciation, which is one reason the loss of water clarity in modern Lake Victoria is so damaging: where females can no longer distinguish male colours, reproductive isolation between closely related species breaks down.
Breeding
Labrochromis teegelaari is a maternal mouthbrooder, as FishBase records and as is universal in the Lake Victoria haplochromine flock. No clutch count was published for this species specifically; congeneric Victoria haplochromines of similar size are small-clutch brooders, typically producing on the order of a few dozen relatively large eggs (commonly around 20–60). In the usual haplochromine pattern the female lays a small batch, takes the eggs into her mouth, and — cued by the male's anal-fin egg-dummy markings — collects sperm to fertilise them inside her buccal cavity. She then carries the developing eggs and larvae in her mouth for several weeks without feeding, releasing free-swimming fry that may continue to shelter in her mouth when threatened. Parental care is therefore entirely maternal and post-spawning; the male contributes nothing after fertilisation. The specific egg number, brooding period and fry size for teegelaari were never documented before the population collapsed.
In the aquarium
Labrochromis teegelaari is effectively never kept in the aquarium. It is a small, narrowly distributed Lake Victoria endemic that was scientifically described and then largely lost from the lake within a few years; it has no presence in the ornamental trade and there is no body of hobbyist husbandry to report for it. What is kept in the Victoria-basin hobby are a handful of more colourful, more widely collected haplochromines and a number of named but undescribed forms, several of them maintained partly as conservation populations in zoos and aquaria after their wild numbers crashed. For those Victoria haplochromines that are kept, the general recipe is hard, alkaline water (pH around 7.5–8.5, moderate to high hardness) at roughly 75–81 °F, ample swimming room, a sand bottom and the heavy filtration these robust, boisterous fish demand; males are aggressive and are best run with a surplus of females. None of that has been verified for teegelaari, which should be regarded as an extinct or possibly-extinct wild species rather than an aquarium fish.
Conservation
The IUCN Red List assesses Labrochromis teegelaari as Critically Endangered (Possibly Extinct) under criterion C2a(ii), assessed on 31 March 2010 by Witte, de Zeeuw and Brooks, with a decreasing population trend. The primary threat is predation by the introduced Nile perch (Lates niloticus), whose explosive increase from the 1980s onward coincided with the near-total disappearance of haplochromines from the sub-littoral and offshore waters of Lake Victoria — precisely the soft-bottom sub-littoral zone this species inhabited. A second, compounding threat is hybridisation driven by declining water transparency: eutrophication, erosion and sedimentation have clouded the lake, eroding the visual mate-recognition cues that keep closely related species reproductively separate, so that distinct forms can merge. The fish is also taken incidentally in the lake's fisheries, though it is not a target. Eschmeyer's Catalog of Fishes now flatly records the species as extinct. Whether any population survives is unknown; like much of the Lake Victoria flock, teegelaari stands as a marker of one of the most rapid vertebrate extinction episodes of the modern era.