Taxonomy & naming
Albert Günther described this fish as Rubricatochromis guttatus in 1862, in the fourth volume of his Catalogue of the Fishes in the British Museum, from syntypes held at the Natural History Museum, London (BMNH 1860.4.17). The accompanying locality data were garbled — the register reads "Cape Colony, South Africa," which is far outside the species' true West African range and is universally regarded as an error of labelling rather than evidence of a southern population. For most of the twentieth century guttatus was treated as a junior synonym of Hemichromis bimaculatus Gill, 1862, and that name, not guttatus, became the one printed on dealer tanks, in beginner books, and in the physiology and ethology papers that used "Hemichromis bimaculatus" as a laboratory animal. The American ichthyologist Paul Loiselle untangled the muddle. In his 1979 revision of the genus he argued that the fish aquarists actually keep and breed is guttatus, and that true bimaculatus — described from a single, poorly preserved specimen of unknown origin, probably Liberia — is essentially unidentifiable from living material and may never have been in the hobby at all. That reading is now standard: the common trade jewel is Rubricatochromis guttatus, and "Hemichromis bimaculatus" on an aquarium label should be read as this species unless proven otherwise. The deepest change came in 2022, when Anton Lamboj and Stephan Koblmüller published a molecular phylogeny in Hydrobiologia and split the old genus in two. The elongate, five-spotted predators (the Hemichromis fasciatus group) keep the name Hemichromis; the smaller, oval, three-spotted jewels were moved to a new genus, Rubricatochromis, with guttatus designated its type species. Eschmeyer's Catalog of Fishes now lists the fish as Rubricatochromis guttatus (Günther, 1862). We retain the long-familiar Rubricatochromis guttatus here while flagging the current combination, since the great majority of the literature and the entire hobby still use the older name.
Morphology
This is a small, robustly built cichlid: FishBase gives a maximum of about 4.5 in standard length, and aquarium fish usually top out near 4–5 in total length, with females a little smaller than males. The body is oval and laterally compressed — comparatively deep-bodied next to the elongate, pike-like Hemichromis fasciatus group, a shape difference that helps separate the two genera at a glance. The mouth is small and only moderately protrusible, the snout short and obtuse, scarcely longer than the eye. Fin counts run to roughly XIII–XV spines and 9–12 soft rays in the dorsal and III spines with 7–9 soft rays in the anal. Out of breeding condition the fish is an unremarkable yellowish to olive-brown, but the markings are diagnostic: a large dark blotch on the gill cover, a second oval blotch in the middle of the flank (occasionally faint or absent), and usually a small ovoid spot on the caudal peduncle — the "three-spot" pattern that defines the jewels. Small round black spots speckle the sides of the head. Scattered irregularly across the head, body and unpaired fins are the iridescent blue-green spangles that give the fish its name and that, in good light, blaze against a flushed body. Anton Lamboj has noted that those blue dots are one of the more reliable field marks separating guttatus from its near-identical eastern lookalike Rubricatochromis letourneuxi, which generally lacks them. The transformation comes with breeding: both sexes intensify to a deep, glowing red, the female often the more vividly coloured of the pair, and the spangling stands out like sparks. Sexual dimorphism is otherwise modest — males average larger with somewhat more produced finnage, while ripe females are visibly rounder — and sexing non-breeding fish reliably is difficult.
Habitat
Rubricatochromis guttatus is a fish of the coastal rivers of West Africa, distributed from Sierra Leone east to Cameroon and inland to the Central African Republic, conspicuously absent only from the Lower Volta basin within that belt. It is forest-associated but eurytopic — a generalist that turns up across a wide spread of lowland waters rather than a habitat specialist. Loiselle characterised it as most frequently found among stands of emergent or submerged plants, particularly abundant in the shallower, quieter stretches of large rivers, in small lateral tributaries, in oxbow lakes, and in swampy backwaters; it even maintains breeding populations in coastal lagoons and brackish estuary margins. It is correspondingly scarce in the fast, rocky rapids zones and absent from cold headwater streams running through montane forest. Most of the range lies under tropical forest, but the genus as a whole stretches into drier savanna, and the species tolerates a striking chemical envelope. Its core habitats are warm, soft and acidic — the tea-stained blackwaters of the forest — yet guttatus is one of the more adaptable jewels and is also recorded in hard, alkaline water; across the genus, in-situ pH spans roughly 4 to 8.5 and water temperatures range from about 64 °F up to the low 30s, though the species sits typically in the warm 75–81 °F band. These are shallow-water fish, found in the upper metre or two of stream, swamp and lagoon margins rather than in any deep, open-water zone. An isolated introduced population persists in a warm spring-fed stream at Villach, Austria, where it was released around 1970.
Feeding
The jewel cichlid is an opportunistic omnivore that forages over the bottom and among vegetation for whatever small live prey it can take. Stomach studies of the genus point chiefly to insects — aquatic insect larvae and terrestrial insects that fall to the water — together with sand, detritus, and other small invertebrates; juveniles take more algae, copepods, water mites and tiny larvae before shifting to the adult diet. The diet is plastic. Paul Loiselle observed that snails turn up in the gut contents of guttatus, and the related Rubricatochromis letourneuxi from hard-water Egyptian lakes develops massive molariform pharyngeal teeth for crushing shells — a flexibility in feeding apparatus that tracks the genus's wide habitat tolerance. In its forest-stream communities the species works as a mid-sized invertivore of the shallows and vegetated margins, gleaning insect larvae from leaf litter and plant stems and snapping at anything small enough to swallow. In the aquarium that translates into an undemanding feeder that accepts essentially any prepared, frozen or live food offered.
Mating
Outside of breeding, jewel cichlids can be relatively retiring — even shy in the wild, sheltering among plants, wood and roots — but reproduction flips a switch. Pairs form through a mutual courtship in which both fish flush red and circle one another, presenting flanks over a chosen flat surface on the bottom, breaking off to swim away in parallel, then returning to circle again moments later; Juan Miguel Artigas Azas described exactly this display in a wild pair watched over a flat rock in a Mexican spring where the species has become established. Pairs can form at any time of year — wild pairings have been recorded year-round — so the fish has no fixed breeding season and will spawn whenever conditions and condition allow. Once a pair has bonded it claims and defends a territory that is conspicuously large for so small a cichlid, and the mood turns combative: spawning jewels are notoriously aggressive toward anything that approaches the site, including each other before the bond is firm and any tankmate afterward. This unpredictable intraspecific aggression — a mismatched or unready pair can fight savagely — is the central challenge in keeping and pairing the species, and the reason the gentle-looking jewel has such a fierce reputation among aquarists.
Breeding
Rubricatochromis guttatus is a monogamous, biparental open-substrate spawner. The female lays a few hundred small oval eggs — measured at about 1.4 by 0.5 in — onto a pre-cleaned hard surface such as a flat stone, a piece of wood, or the floor of a cave; reported clutches run from roughly 200 to 300, reaching about 400 in large females, a modest count by the standards of substrate-spawning cichlids. Both parents guard the plaque intensely. Eggs hatch in about two to three days, after which the parents lift the wrigglers in their mouths and move them between several pre-dug pits around the spawning site, shuttling them as needed. The young are free-swimming roughly five days after spawning and begin moving as a herded cloud a day later, shepherded by both parents; fry of the genus carry a distinctive dark lateral stripe, broader toward the tail, that darkens with age. Parental care is prolonged and attentive, with the pair guarding larvae and free-swimming young for around four weeks. One curious behaviour has been documented more than once: when only twenty or so fry remain, the female may repeatedly take them into her mouth for spells of around half an hour — an incipient, facultative form of mouthbrooding reported across several jewel species, hinting at how mouthbrooding might evolve from substrate guarding. In aquaria the fish breeds readily once a compatible pair settles; heavy feeding and frequent water changes bring a female into the deep-red condition that signals readiness, and she will then clean a surface and spawn, often producing the next clutch within weeks of the last.
In the aquarium
The jewel cichlid is one of the oldest and most widely available African cichlids in the hobby — exports of guttatus from Nigeria began in the 1960s, and Loiselle introduced the species to American aquarists in 1971 — and two-inch juveniles are still cheap and easy to find. None of that makes it a beginner's community fish. It is hardy, undemanding about water chemistry, and trivial to feed, but it is also among the more aggressive small cichlids, and that single trait dictates how it should be kept.
For a pair, plan on a tank no smaller than about 30 US gallons (roughly 30 US gal) and ideally a metre long; footprint matters more than volume, and a larger floor area makes managing the fish considerably easier. Aquascape with a fine sand substrate, rounded rocks, driftwood and roots, and a flat stone or a half-buried cave or flowerpot to serve as a spawning surface; plants help by breaking lines of sight and giving subordinate fish places to hide, and the species is no great threat to robust planting outside of spawning. Because these fish are shy in nature, a few sturdy dither fish — large characins or other fast, fin-intact midwater fish too big to be eaten or harassed — settle them and draw them into the open; the jewels pose no danger to tankmates of that sort while not breeding.
Water chemistry is the easy part. Although wild populations favour soft, acidic, warm water, that is not a requirement in captivity — the species thrives across a broad range, and what matters far more is low dissolved waste and good oxygenation. A temperature of about 75–81 °F suits both maintenance and breeding, pH anywhere from the low 6s to the high 7s is fine, and the species will even live and spawn in hard, alkaline water. Frequent, generous water changes do more for the fish's health and colour than any attempt to chase a particular pH.
The real difficulty is social. A spawning pair becomes intensely territorial and will drive off, injure, or kill tankmates and even an ill-matched mate; jewels are emphatically not general community fish, and a breeding pair is best given a tank of its own or a large one with abundant cover and escape routes. The most common ways keepers lose these fish are housing two unready or mismatched adults in cramped quarters, or expecting a peaceful community to survive a spawning. Manage the aggression — space, sightline breaks, dithers, and a ready divider when pairing unfamiliar fish — and the jewel cichlid is a durable, brilliantly coloured, free-breeding fish that rewards a keeper willing to work around its temper.
Conservation
Rubricatochromis guttatus has not been evaluated by the IUCN Red List — under either its current name, Rubricatochromis guttatus, or the older Rubricatochromis guttatus, a live search of the Red List returns no assessment, and Eschmeyer's Catalog of Fishes likewise records it as Not Assessed. No formal conservation status, population trend, or threat analysis therefore exists for the species. The indirect signals are reassuring rather than alarming: it is widespread across the coastal rivers of West Africa from Sierra Leone to Cameroon, ecologically flexible across a very broad range of water chemistry and habitat types, abundant where it occurs, and bred in such quantity for the aquarium trade that wild collection pressure is negligible. FishBase rates its resilience as high. As with most lowland West African fishes, the realistic long-term pressures are habitat-level rather than species-specific — deforestation of the forest-river belt, pollution, swamp drainage, and the steady degradation of coastal lagoon and floodplain habitat — but none of these has been documented as a present threat to this adaptable, generalist cichlid.