Taxonomy & naming
Haplochromis igneopinnis was described in 1998 by Ole Seehausen and Erwin Lippitsch (with N. Bouton and H. Zwennes) in their landmark monograph 'Mbipi, the rock-dwelling cichlids of Lake Victoria: description of three new genera and fifteen new species' (Ichthyological Exploration of Freshwaters 9(2):129–228). The original combination placed the fish in the new genus Pundamilia, and Eschmeyer's Catalog of Fishes lists it as valid under that name — Pundamilia igneopinnis Seehausen & Lippitsch, 1998. FishBase and several regional databases instead retain it in the catch-all genus Haplochromis, following van Oijen's (1996) conservative classification of the Lake Victoria flock, which holds that the great majority of these species should stay in Haplochromis until a complete revision is published. We keep the Haplochromis heading here for consistency with that broad usage while noting that Pundamilia is the genus of original description and the name under which the fish is most often discussed in the speciation literature. Pundamilia is the same genus that contains the celebrated Pundamilia nyererei / Pundamilia pundamilia 'red–blue' species pair, the textbook example of cichlid speciation by sexual selection on male colour. Within that radiation, Haplochromis igneopinnis is one of the 'mbipi' — a Swahili-derived term Seehausen adopted for the rock-dwelling cichlids of the lake. No synonyms are recognized.
Morphology
This is a small cichlid: FishBase gives a maximum of 4.5 in standard length, and most individuals are smaller. The body is fusiform and laterally compressed in the typical haplochromine plan, with meristics of 16–17 dorsal spines and 9–10 dorsal soft rays, 3 anal spines and 8–10 anal soft rays, and 30–31 vertebrae. Coloration is the species' signature and the source of its name: breeding males are deep, sooty black to blackish over the body, set off by vivid orange to flame-red fins — pelvic, anal and parts of the dorsal and caudal — a contrast that the describers themselves singled out ('bright-orange fins surrounding a deep-black body'). Aquarists who have collected the fish note a striking orange-finned variant from Ndurwa Point. Sexual dimorphism is marked, as in nearly all Lake Victoria haplochromines: the colourful black-and-orange males are the displaying sex, while females are drab and cryptic — a plain silvery to brownish-grey, the better to carry and shelter a brood unnoticed. The bright male livery is not mere decoration; in this flock it is the visual cue females use to recognize and choose mates of their own species.
Habitat
Haplochromis igneopinnis is narrowly endemic to the southwestern shores of the Speke Gulf, in the Tanzanian sector of Lake Victoria — the only known range, placing it squarely within the Lake Victoria Basin freshwater ecoregion. It is a strict rock-dweller, occurring only over rocky substrates of medium-sized to very large boulders. FishBase records two related microhabitats: on moderately steep shores it keeps to slightly offshore areas beyond about 7 ft depth, while on steep rocky shores it lives immediately inshore in the deep, wide gaps between big boulders. Breeding males hold territories among large boulders at roughly 10–13 ft depth or deeper. Lake Victoria is warm, alkaline tropical freshwater; across the lake's haplochromine habitats water temperatures generally run about 73–81 °F and pH is mildly to strongly alkaline (roughly 7.2–9.0), with the rocky littoral that this species occupies being clear-water habitat where light penetration matters for the colour-based mate choice that structures the flock. The progressive loss of that water clarity — through eutrophication, erosion and sedimentation — is precisely the change that now threatens it.
Feeding
Haplochromis igneopinnis is a low-trophic-level grazer of the rocky zone. FishBase reports that it feeds on algae and detritus and estimates a trophic level of about 2.0, the lowest end of the scale, consistent with a fish that works the algal mat (the 'aufwuchs') and accumulated organic matter on and between boulders rather than hunting prey. This places it among the epilithic algae-and-detritus feeders of the Lake Victoria flock — a guild that, in Witte's classic ecological partitioning of the 300-plus haplochromine species, occupies the rocky substrates and gleans the periphyton growing on hard surfaces. Despite the popular reading of the 'fiery fins' as a predator's warning, the dietary evidence makes this a peaceable grazer; the orange is for courtship, not for hunting. In the rocky community it shares the boulder zone with numerous other small haplochromines, ecological coexistence being maintained by fine differences in microhabitat and diet among the many sympatric species.
Mating
Reproduction follows the polygynous, male-territorial template that runs through the Lake Victoria rock cichlids. Males establish and defend territories among the big boulders at about 10–13 ft depth or deeper, and from these stations the black-bodied, orange-finned male displays to passing females. There is no pair bond and no paternal care: a male courts and spawns with multiple females, and his bright nuptial colour is the central signal of the encounter. In this flock female mate choice operates strongly on male coloration, and the clarity of the water is what allows that choice to function — females discriminate among males, and against males of similar-looking sister species, by their colours. This is the mechanism that underpins the famous Pundamilia work on speciation by sexual selection, and it is also the species' Achilles heel: where water turbidity blurs the colour signal, females can no longer tell the species apart and mismatched pairings occur.
Breeding
Like essentially all Lake Victoria haplochromines, Haplochromis igneopinnis is a maternal (female) mouthbrooder with maternal-only parental care. After a male's courtship display over his rocky territory, the female lays her eggs and immediately takes them into her mouth; fertilization in this lineage typically involves the female mouthing 'egg-dummy' spots on the male's anal fin, drawing in milt to fertilize the clutch she already holds. She then carries the developing eggs and larvae in her buccal cavity for the incubation period — on the order of two to three weeks in these small haplochromines — releasing fully formed, free-swimming fry, with no contribution from the male. Specific clutch counts for this species have not been published; congeneric Lake Victoria rock cichlids of comparable size are modest-fecundity brooders typically producing on the order of a few dozen eggs per spawn, the small clutch being the trade-off for the safety of oral incubation. The fry are small at release and grow on the algal and micro-invertebrate fare of the rocky littoral.
In the aquarium
Haplochromis igneopinnis is rarely kept. It has occasionally appeared in the specialist Lake Victoria hobby — the Cichlid Room Companion carries a profile with an aquarium photograph of a male — but it is not a fish of the general trade and is seldom offered commercially. Where Victorian haplochromines of this type are maintained, the husbandry is well understood: hard, alkaline water (pH roughly 7.5–8.5) at about 75–81 °F, a rocky aquascape of piled stone giving territories and line-of-sight breaks, and a footprint generous enough to spread out the aggression of a colony. They are best kept as one male with several females, or as a group in a larger tank, so that subordinate fish and brooding females can escape a dominant male. Diet is easy — a small omnivore-grazer, it takes quality flake and pellet, spirulina-based and vegetable foods, and small frozen items, with an emphasis on the algal/vegetable side that matches its wild grazing. The two cautions are the ones that attach to all Victorians. First, they hybridize readily: never house Haplochromis igneopinnis with other Lake Victoria haplochromines (especially other Pundamilia), because under aquarium lighting and in mixed company the species-recognition that keeps them distinct in clear lake water breaks down and crossbred fry result — a serious problem for a fish whose wild populations are themselves threatened by hybridization. Keep it as a single-species colony if the intent is to maintain or propagate clean stock. Second, like its relatives it can be quarrelsome at spawning time, so provide cover and numbers. For a conservation-minded aquarist this is a worthwhile project fish; for everyone else it is a hard-to-source rarity.
Conservation
The IUCN Red List assesses Haplochromis igneopinnis as Endangered (EN, criteria B1ab(iii,v)+2ab(iii,v); assessed 1 April 2010, by Witte, de Zeeuw and Brooks of the Freshwater Biodiversity Unit). The listing reflects both a very small geographic range — restricted to the southwestern Speke Gulf — and the specific way Lake Victoria's environmental crisis bears on this fish. The assessors identify the main threat as hybridization driven by decreased water transparency: eutrophication, erosion, sedimentation and runoff have clouded the lake, and turbid water interferes with the colour-based visual cues that females use to recognize mates of their own species, eroding the reproductive boundaries between closely related haplochromines. A second, more direct threat is capture as bait for the long-line fishery. Behind these sits the broader catastrophe of the Lake Victoria cichlid flock: the introduction of the predatory Nile perch (Lates niloticus), whose explosive increase through the 1980s — compounded by eutrophication — drove the collapse and probable extinction of a large fraction of the lake's several hundred endemic haplochromine species in one of the best-documented vertebrate mass extinctions of modern times. As a narrow-range rock-dweller dependent on clear water for its very reproduction, Haplochromis igneopinnis is among the species for which that ongoing degradation is the defining conservation concern.