Cichlid Atlas — the world's cichlid waters, in depth

Taxonomy & naming

Belgian ichthyologist Max Poll described this fish in 1948 as Haplotaxodon tricoti, working from specimens collected during the Belgian Hydrobiological Mission to Lake Tanganyika in 1946–1947. The species epithet honors a Monsieur Tricot, director of the Great Lakes Railroad Company at Albertville, who supported that expedition. Poll later erected the genus Benthochromis for it; the name fuses the Greek benthos ("the deep") with chromis (an old word for a perch-like fish), a fitting label for a cichlid of the lake's lower layers. It anchors its own small tribe, the Benthochromini, within the African cichlid subfamily Pseudocrenilabrinae. To the fishers of the lake it is the "Tambatamba" or "Kamdomo."

The genus has a tangled history. For decades B. tricoti was treated as the lake's only featherfin Benthochromis, and the names Perissodus burgeoni (David, 1936) and Perissodus gracilis (Myers, 1936) were folded into its synonymy. Then Tetsumi Takahashi, in a 2008 paper in the Journal of Fish Biology, described a second species, Benthochromis horii, separating it on the basis of relative eye and snout proportions. Andersen (2013) went further, arguing that three distinct Benthochromis species coexist — tricoti, horii, and B. melanoides — all of them netted from deep water in the southern lake. Ad Konings, who had earlier agreed with Patrick Tawil that tricoti and horii were one fish, reversed himself after personally examining a single true tricoti pulled from a net alongside forty B. horii: it was larger, deeper-bodied, and carried only two pale longitudinal lines where horii shows three. That distinction matters for hobbyists, as explained below.

Appearance

Benthochromis tricoti is a laterally compressed, fusiform cichlid built for hovering rather than dashing. Mature males trail long, filamentous extensions on the dorsal and anal fins — the "featherfin" look the genus shares with Cyathopharynx — and develop blue-grey longitudinal lines along the flanks set against a yellow-tinged throat, while females remain plain and largely silver. The diagnostic features Takahashi used to separate it from its congeners are subtle: the eye is as long as or longer than the snout (101–129% of snout length), there are usually 28–29 total dorsal-fin rays, and the body carries two pearl-grey lines rather than three. Fin counts run to 16–18 dorsal spines, 11–12 dorsal soft rays, three anal spines, and 9–11 anal soft rays.

Size is where the sources genuinely disagree. FishBase lists a maximum of 6.5 in (16.5 cm) total length, and the IUCN assessment repeats that 16.5 cm figure for the species as a whole — yet the same assessment also describes territorial males of 8–10 in (20–25 cm), and hobby accounts routinely cite males of around 8 in (20 cm). The most honest reading is that males reach roughly 8 in (20 cm) and clearly outgrow the considerably smaller females, with the lower published maxima probably reflecting smaller measured samples. Either way, this is a large, slow-moving cichlid that needs room.

Range & habitat

The species is endemic to Lake Tanganyika and, despite its scarcity in collections, is distributed widely around the lake — recorded from the Burundian, Congolese, Tanzanian, and Zambian waters that the lake's four nations share. It is a deep-water fish: the IUCN gives a depth band of roughly 80–660 ft (25–200 m), Konings reports it down to at least 200 m, and observers note the largest aggregations at around 330–490 ft (100–150 m). It favors large rocky slopes and "rich" substrates but ranges out over open water as a benthopelagic, semipelagic schooler.

That depth is not a trivial detail. Fish brought up from 100-plus meters cannot simply be hauled to the surface; collectors must decompress them over a day or more in stages, and a too-rapid ascent kills them outright. In situ the water is warm and alkaline — FishBase notes an environmental range of about 23–25 °C (73–77 °F), consistent with Tanganyika's hard, buffered, pH ~8–9 water. As a creature of the lake's twilight zone, B. tricoti lives much of its life in conditions of low light and, increasingly, near the edge of the lake's oxygenated layer.

Ecology & diet

Benthochromis tricoti is a planktivore. In the wild it feeds on zooplankton and small crustaceans and invertebrates picked from the water column, a diet that places it at a trophic level of about 3.5 — a mid-water carnivore rather than an apex predator. Its slender body, large eye, and protrusible mouth all fit a fish that hunts small, dispersed prey in dim, deep water, hovering and picking rather than chasing.

Ecologically it occupies the semipelagic plankton-feeding guild over deep rocky habitat, a niche it shares loosely with the lake's Cyprichromis and featherfin Cyathopharynx but at greater depth. Schooling — reported flocks of 30 to 100 fish — is the usual strategy for a planktivore in open water, providing both foraging efficiency and safety in numbers from the lake's deep-water predators such as Bathybates and Hemibates. Within the Tanganyika food web it is a link converting plankton production into prey for larger piscivores.

Behavior & breeding

Socially, B. tricoti lives in schools, with dominant males establishing and defending spawning territories to court females; outside of breeding, smaller groups and harems are reported. It is a maternal mouthbrooder. Males display over a chosen site — often the top of a rock rather than a pit in the substrate — and a female who spawns takes the eggs into her mouth to incubate them. Clutches are strikingly small, on the order of 5 to 15 eggs, far fewer than the broods of many rock-dwelling cichlids.

Much of its reproduction happens out of sight. Takahashi and Konings both note that the species may spawn at depths too great for brooding females to turn up in shallow net catches, and Konings has speculated that, like other deep-water Tanganyikan breeders such as Bathybates and Trematocara, it courts in conditions where color is reduced to black and white — which would explain why the one wild tricoti he examined showed only stark markings rather than the bright nuptial dress of its shallower relatives. The small clutch size and deep, low-light spawning are consistent with a fish adapted to a stable, resource-thin environment.

In the aquarium

Start with the identity problem: as keepers themselves point out, true B. tricoti is almost never in the trade. The featherfin "tricoti" sold and bred in the hobby is overwhelmingly Benthochromis horii, the shallower-water species that actually shows up in collectors' nets. Anyone genuinely keeping wild tricoti has an uncommon fish on their hands.

Whatever the label, this is a large, deep-water schooler and not a beginner's cichlid. Keepers converge on a 6-foot tank as the bare minimum and an 8-foot (roughly 180–220 US gallon, ~700–800 L) tank as more appropriate, housing a group of six or more so the natural schooling behavior emerges. They want calm, dim conditions and gentle tankmates: experienced aquarists report that boisterous companions — even spawning Cyprichromis — will harass and stress them, and several describe losing fish that way. Cyathopharynx, smaller Paracyprichromis, and other peaceful sandsifters are more sympathetic neighbors. Water should mirror the lake: hard, alkaline (pH ~8.5–9), and warm (about 24–26 °C / 75–79 °F). Feed small foods that suit a planktivore — frozen mysis, krill, Artemia, and quality flake or micro-pellets.

Breeding is the real challenge. Spawnings do occur in aquaria, often a day or two after a water change, but keepers repeatedly report females spitting tiny clutches early and fry that fail to grow past 2–3 cm, so raising young to size is harder than triggering a spawn. The combination of a big footprint, a need for tranquility and subdued light, slow growth, and stubborn fry makes B. tricoti — and its hobby stand-in B. horii — a project for a dedicated, patient keeper rather than a community centerpiece.

Conservation

On its own account, Benthochromis tricoti is in reasonable shape. The IUCN Red List assessed it as Least Concern in March 2025 (assessment by D. Mushagalusa, published 2025), citing a wide distribution throughout Lake Tanganyika, occurrence in many habitats, and no major lake-wide threats; it carried the same Least Concern rating in 2006. The species does face localized pressure: it is caught by artisanal gillnet and seine fishers — in quantity in July–August after the lake mixes and brings deep-water fish within reach — and is often salted for inland trade in DR Congo, while a trickle enters the international ornamental market. Habitat disturbance and siltation are noted as localized threats. None of these currently rises to a population-level concern for a fish this widespread.

The larger story is the lake itself. Lake Tanganyika is warming, and that warming strengthens the thermal stratification that normally lets deep, nutrient-rich water mix back to the surface. O'Reilly and colleagues (2003, Nature, DOI 10.1038/nature01833) found that reduced mixing has cut primary productivity by roughly 20%, implying on the order of a 30% decline in potential fish yields — a serious matter for a lake that supplies much of the animal protein for the four countries around it through its clupeid (Stolothrissa and Limnothrissa) and Lates pelagic fishery. Cohen and colleagues (2016, PNAS, DOI 10.1073/pnas.1603237113) showed that the same warming has shrunk the oxygenated benthic habitat in their study areas by about 38%, squeezing the deep, oxygen-dependent zone toward shallower water; sedimentation from shoreline deforestation further degrades the rocky littoral (Cohen et al. 1993). Governance of these shared pressures falls to the four-nation Lake Tanganyika Authority. For B. tricoti, a deep-water, rocky-slope planktivore, this matters directly: a fish that lives near the lower edge of the oxygenated layer is precisely the kind of species a contracting oxygen zone and falling deep-water productivity would pinch first. So the honest summary is this — the species is Least Concern today, but it lives in a lake under measurable strain, and its deep, oxygen-limited niche makes it one to watch rather than one to dismiss.

Benthochromis tricoti

About this species