Taxonomy & naming
The species was described by the Belgian ichthyologist Dirk Thys van den Audenaerde in 1970, as Tilapia coffea, from the St. Paul River drainage of Liberia. The epithet is a toponym, not a Latin word for the body or the drink: it refers to Mount Coffee Dam Lake on the St. Paul River, the type locality — the reservoir of the Mount Coffee hydropower scheme some 16 mi upstream of Monrovia. The name therefore ties the fish, from the outset, to a single dammed stretch of one Liberian river.
Like its relatives, coffea was originally placed in the oversized genus Tilapia and later moved when Dunz and Schliewen's molecular phylogeny (2013, Molecular Phylogenetics and Evolution 68) broke up that assemblage and resurrected Coptodon Gervais, 1853 for the substrate-spawning West and Central African tilapias. Tilapia coffea became Coptodon coffea, the combination used by Eschmeyer's Catalog of Fishes and FishBase. It is one of two Coptodon endemic to the St. Paul system, alongside the more widespread Coptodon louka that also reaches the drainage.
Morphology
Coptodon coffea is a small-to-medium tilapia, reaching about 6.5 in in total length (FishBase). It has the standard Coptodon build — a moderately deep, laterally compressed body with a single long dorsal fin — and the genus's diagnostic lower pharyngeal jaw, which is roughly as long as broad, with the anterior lamella shorter than the toothed area and the median pharyngeal teeth not broadened. The meristics give 13–15 dorsal spines and a notably high count of 14–17 soft dorsal rays (mean about 14), three anal spines and 9–11 anal soft rays, with 9–12 lower gill-rakers.
The most useful field mark is the fin patterning: in coffea the dorsal and caudal fins are densely blotched — heavily speckled with dark markings — which separates it from congeners such as louka whose fins are unmarked or only feebly spotted. As in all Coptodon the body carries vertical barring rather than horizontal stripes. Detailed accounts of live coloration, breeding dress and sexual differences are limited for this rarely studied fish, so it is best diagnosed on the combination of its densely blotched fins, its meristics, and its St. Paul River provenance rather than on a distinctive overall colour.
Habitat
This is a freshwater, demersal (bottom-associated) fish, and a true single-river endemic: FishBase records it as 'at present only known from and probably endemic to the St. Paul River, Liberia,' between roughly 6° and 8° N. The St. Paul is one of Liberia's principal rivers, draining the Upper Guinean forest block of high freshwater endemism, and coffea's type locality lies specifically in the impounded reach behind the Mount Coffee dam. Confinement to a single drainage — and a dammed one at that — is the central fact of the species' ecology and the root of its conservation problem.
As a demersal cichlid it lives close to the river bed, and as a substrate spawner it depends on workable sediment for nesting. Beyond that, the fine detail of its preferred microhabitat — substrate type, depth, current — is sparsely documented in the accessible literature. What is clear is that the species has nowhere else to go: its entire known world is one river, much of it altered by impoundment, which leaves it acutely exposed to anything that degrades that single system.
Feeding
No dedicated dietary study of Coptodon coffea has been published, and FishBase carries no quantified diet for the species; its trophic level (about 2.6) is an estimate based on body size and the diets of close relatives rather than on gut-content data. The genus Coptodon is dominated by herbivores and detritivores, and a St. Paul River endemic of this lineage would most plausibly feed as a grazer — taking the algal and biofilm growth on submerged stones and wood, soft plant matter, and the detritus of the river bed, with incidental small invertebrates. That is a reasonable inference from the genus and the habitat, but it should be read as inference: the specific feeding ecology of coffea has not been documented, and the figures here are modelled rather than measured.
Mating
Coptodon coffea is understood to be a pair-bonding substrate spawner, in keeping with the genus and unlike the mouthbrooding food-tilapias. FishBase summarises its reproduction as 'probably pair-bonding, open substratum spawner, with both parents guarding the brood' — the 'probably' signalling that the behaviour is inferred from close relatives rather than directly observed in coffea. In the Coptodon pattern a male and female form a monogamous pair, jointly clean and defend a nest site, and hold a territory through the breeding cycle. The specifics of courtship, pair formation and territoriality have not been recorded for this species, so the account rests on the consistent biology of its better-known congeners rather than on field observation of coffea itself.
Breeding
Reproduction is biparental open-substrate spawning: in the genus pattern, adhesive eggs are laid on a cleaned surface or in a cleared depression and are tended by both parents, which fan the eggs and guard the wrigglers and free-swimming fry. FishBase applies exactly this characterisation to coffea, with the cautious 'probably.' Quantitative breeding data — clutch size, egg dimensions, the timing of the spawning season, fry development — have not been published for the species, and there are no aquarium breeding reports. The reliable statement is the qualitative one: coffea is placed among the biparental substrate-spawners by genus membership and FishBase's summary, but its breeding has not been directly studied, in the wild or in captivity.
In the aquarium
Coptodon coffea has no real presence in the aquarium hobby. It is not a trade species, has no aquarium-strain history, and — as a Critically Endangered single-river endemic — is precisely the kind of fish that should not be entering the ornamental trade. There is no body of keeper experience for it, so any husbandry note is inference from its biology rather than tested practice.
In general terms, a fish like this would need a tank scaled to a 6.5 in substrate-spawning cichlid: a long footprint, a sand substrate it can work, warm water in the high 20s Celsius to match its Liberian forest-river origins, strong filtration, and a vegetable-leaning diet consistent with the genus's herbivorous tendency. As a substrate spawner it would become territorial around breeding. But these are extrapolations from habitat and relatives; the practical and ethical reality is that coffea is a Critically Endangered wild endemic, not an aquarium subject, with no hobby track record to report.
Conservation
Coptodon coffea is assessed by the IUCN Red List as Critically Endangered (criteria B2ab(iii)), assessed on 17 August 2019 — the most severe category short of extinction, and an extraordinary status for a tilapia. It follows directly from the fish's biology: a species known only from the St. Paul River of Liberia, with a very small area of occupancy, facing a continuing decline in the quality of its habitat. The B2ab(iii) criteria flag a tiny, declining range with deteriorating habitat conditions. The pressures on the St. Paul are acute — the Mount Coffee dam at its type locality alters flow and connectivity, and the wider drainage faces deforestation, mining, pollution and the siltation that come with them, all of which bear hardest on a fish with no second population to fall back on. The species carries no CITES listing and is of no fishery interest, but its combination of single-river endemism and a heavily modified home river makes it one of the most genuinely imperilled cichlids of West Africa, and a clear conservation priority.