Taxonomy & naming
Sciaenochromis sp. "Small Interorbital" is not a formally described species and has no entry in Eschmeyer's Catalog of Fishes. It belongs to Sciaenochromis, a genus of predatory Lake Malawi haplochromines erected by David Eccles and Ethelwynn Trewavas in 1989, containing only four valid described species — S. ahli, S. benthicola, S. fryeri and S. psammophilus — alongside roughly a dozen recognised undescribed forms. Its trade name reports a specific anatomical measurement, interorbital width (the space between the eyes across the top of the head), as narrower than usual for the genus — a meristic, ruler-and-calipers character of exactly the kind field researchers and collectors fall back on when colour and gross body shape are not enough to separate cryptic Sciaenochromis populations. This population is recorded from Wissman Bay on the Tanzanian shore, at the genus's northern range limit, and has not been matched with confidence to any described species.
Morphology
This form shares the genus's fusiform, torpedo-shaped body and relatively large, slightly projecting jaws built for hunting small fish. Its defining character is a narrower interorbital width — the bony space between the eyes across the top of the skull — than typical for Sciaenochromis, a subtle anatomical distinction rather than an obvious visual one. Described Sciaenochromis run from about 4.5 in standard length in S. fryeri up to around 8 in total length in S. ahli, and this form is presumed to fall within a comparable size range, though no measurements beyond the interorbital character have been published for it. Colour has not been documented for this population; this account does not extend the vivid blue of S. fryeri or S. psammophilus to it without direct evidence.
Habitat
Sciaenochromis sp. "Small Interorbital" is recorded from Wissman Bay on the Tanzanian shore of Lake Malawi, near the genus's northern range limit. Described Sciaenochromis occupy rocky and rock-sand transition habitat — S. ahli in caves and crevices down to around 492 ft, S. fryeri in intermediate rock-sand zones at roughly 33–131 ft — and this population plausibly occupies broadly similar habitat, though this is inference rather than a confirmed observation specific to Wissman Bay. The surrounding water carries Lake Malawi's characteristic alkaline, well-buffered chemistry.
Feeding
As with other Sciaenochromis, this form is presumed to be a piscivore specialised in hunting small fish rather than grazing algae or sifting sand. The genus sits at a high trophic level — S. ahli and S. fryeri are both placed around trophic level 4.2 on FishBase — among the more predatory niches in the Malawi flock. The best-documented feeding behaviour in the genus is a striking piece of aggressive mimicry: Konings describes S. fryeri stalking prey with a head-down, rocking posture that imitates a harmless algae-grazing fish, drifting closer until within striking range before delivering a sudden sideways strike, and hunting at the margins of kampango (Bagrus meridionalis) catfish nests to pick off the dense clouds of juvenile fish gathered there. Whether this Wissman Bay population, at the genus's Tanzanian range edge, shares that specific hunting technique has not been observed. No feeding study specific to it has been published.
Mating
Courtship has not been observed directly in this population. By analogy with the wider genus, Sciaenochromis are polygynous maternal mouthbrooders with no lasting pair bond, and territoriality is documented as comparatively loose: Konings describes S. fryeri males as only weakly territorial, sometimes carrying breeding colour year-round while defending ground loosely, occasionally gathering in small lek-like clusters to build simple 'cave-crater' bowers — a spawning platform dug into sand against a large rock — with little serious aggression between neighbouring males. Courtship itself is expected to follow the standard haplochromine sequence of lateral display and fin-quivering, with the male's anal-fin egg-spots used to lure the female to mouth at his vent, though the specific display sequence has not been documented for this Wissman Bay population.
Breeding
Sciaenochromis sp. "Small Interorbital" is treated as a maternal mouthbrooder, consistent with its genus and the wider Lake Malawi haplochromine radiation. Following spawning the female takes the fertilised eggs into her mouth and broods them alone; Konings documents a brooding period of roughly three weeks for S. fryeri before she releases free-swimming fry, with no male or biparental care beyond her own. No clutch-size figures have been published for any Sciaenochromis species, including this population, and fry number and size are expected to scale with the size of the brooding female, following the pattern typical of Malawi haplochromine mouthbrooders generally. This account follows genus-level inference rather than direct observation of this population's own breeding behaviour.
In the aquarium
Sciaenochromis sp. "Small Interorbital" is not established in the aquarium hobby with an identity of its own, unlike its famous congener S. fryeri, one of the most widely traded Malawi haps. As a subtle, anatomically-defined field form from a peripheral Tanzanian locality, it is not a fish collectors are likely to target specifically, and any specimens reaching hobbyists would most plausibly be sold as unidentified Sciaenochromis sp. Care would follow the genus template: alkaline, well-buffered water in the mid-to-high 7s to low 8s pH and a predator-appropriate diet with tankmates too large to be treated as prey, but no husbandry information specific to this form has been documented.
Conservation
Sciaenochromis sp. "Small Interorbital" has not been evaluated by the IUCN. As an undescribed form without a published scientific name it has no Red List category or assessment. The genus's two assessed described species, S. fryeri and S. ahli, are both Least Concern (2018), reflecting broad distributions, though the genus as a whole, being endemic to a single lake, remains exposed to the basin-wide pressures of fishing, sediment and nutrient loading and climate-driven warming documented for Lake Malawi. No conservation status beyond "not assessed" should be attached to this form.