Taxonomy & naming
This fish was described by Thomas D. Iles in 1960 as Haplochromis likomae, in his study of the zooplankton-feeding Haplochromis of what was then Lake Nyasa (Annals and Magazine of Natural History, series 13, vol. 2). The type locality is Likoma Island in the northern part of the lake. Iles diagnosed the species within a cluster of subtly distinct utaka, recognizing it by features such as a high gill-raker count, a pointed snout, and a two-spot flank pattern. The name later passed through Cyrtocara before settling in Copadichromis, the genus that Eccles and Trewavas erected in their 1989 revision of the Malawian haplochromine genera; the combination Copadichromis likomae (Iles, 1960) — the authorship in parentheses to mark that the species was first placed in a different genus — is the valid name today (Catalog of Fishes; FishBase). The genus name joins the Greek kopas (-ados), "carved," to Chromis, the classic perch-like fish name long used as a suffix for cichlid genera. Copadichromis is the type of the utaka guild — a Chichewa fisheries term for the open-water, plankton-eating haplochromines — and the genus is notoriously hard to disentangle, with many look-alike species and named geographic colour forms; recent taxonomic work continues to sort it out (for example the 2022 study of the closely allied Copadichromis mloto and Copadichromis virginalis). In the trade Copadichromis likomae is sold under its collecting locality, and the malawi.si database documents additional, still-undescribed "likomae-type" forms (such as a 'likomae masinje' population) around the lake.
Morphology
Copadichromis likomae is a small to mid-sized, fusiform utaka. FishBase, following the CLOFFA checklist (Maréchal 1991), gives a maximum length of about 5.5 in total length, and field observations on Likoma fish put typical adults at much the same size, around 5.5 in; the related, possibly conspecific 'likomae masinje' form is reported a little larger, near 6 in. The body is the streamlined shape of an open-water plankton picker, with the pointed snout and high gill-raker count Iles used to separate it from its congeners, and a characteristic pair of dark flank spots. Coloration is sexually dimorphic in the usual Malawi manner: dominant, breeding males develop a darker overall colour with contrasting lighter areas on the head and fins, while females and non-breeding fish stay a plainer silvery grey with more subdued markings. As in other Malawi mouthbrooders, males carry the genus's egg-spot ornamentation on the anal fin. Because so many utaka look alike and vary by locality, colour alone is an unreliable guide to identity here.
Habitat
The species is endemic to Lake Malawi (also called Lake Nyasa and Lake Niassa), the great rift lake shared by Malawi, Mozambique, and Tanzania. It was described from Likoma Island, and FishBase still characterizes it narrowly as occurring on Likoma; the IUCN assessment, however, treats it as having a lake-wide distribution, and malawi.si maps additional populations away from the island. The honest summary is that it is anchored to the Likoma area in the older literature but is now considered more widespread around the lake. Ecologically it is an inshore, benthopelagic fish: the IUCN notes it remains inshore all year and is caught most often near rocky habitats, while it feeds and shoals in the open water just off the rocks and over the adjacent sand. Like all Lake Malawi cichlids it lives in hard, alkaline, well-buffered water — the lake's surface layer typically runs pH around 8 and roughly 75–79 °F — and as an inshore plankton feeder it stays in the warm, sunlit upper zone rather than the deep water.
Feeding
Copadichromis likomae is a specialist zooplanktivore. FishBase records that it feeds on zooplankton and forms schools, and places it at a trophic level of about 3.4, consistent with a diet of animal plankton rather than algae or detritus. Like the rest of the utaka it works the open water just off the reef, using large eyes to spot individual copepods and other drifting prey and a protrusible, suction-style mouth to pick them out of the current. Ecologically the utaka are a key link in Lake Malawi's offshore food web, converting the lake's planktonic production into fish biomass that supports larger predators and human fishers alike. Because Copadichromis likomae shoals inshore in numbers, it is one of the species that local fishermen target with utaka nets, which ties its ecology directly to the lake's fishery.
Mating
Like other utaka, Copadichromis likomae is a shoaling fish whose social structure reorganizes around male breeding territories at spawning time. Outside of breeding, females and non-territorial fish travel in loose schools through the inshore water column. When ready to breed, mature males move to the bottom and establish and defend spawning sites; malawi.si describes them holding territories close to rocky structures, while the IUCN assessment specifies that breeding takes place in the intermediate habitat between rock and sand, where each male builds a large sand "castle" (a constructed bower) without using any rocks. Males in breeding condition flush into their darker colour and display from these sites to draw females. The species is generally peaceful and becomes territorial mainly during this breeding phase.
Breeding
Reproduction is maternal mouthbrooding, the standard Lake Malawi strategy. A territorial male displays from his sand bower to attract a female; she spawns in batches and immediately takes each batch of eggs into her mouth, and — drawn to the egg-spots on the male's anal fin — collects the milt that fertilizes the clutch inside her mouth. She then carries and broods the developing eggs and larvae alone, without feeding, for roughly three to four weeks as in other Copadichromis, with no paternal care. The IUCN assessment adds a specific natural-history detail for this species: the fry are released in very shallow water among rocks and plants, sheltered nursery habitat for the young. Clutch sizes are not well documented for Copadichromis likomae specifically; utaka of this size typically carry on the order of a few dozen eggs.
In the aquarium
Copadichromis likomae is rarely seen in the hobby. It circulates occasionally as a Likoma Island locality fish, usually lumped loosely with other utaka, and is far less commonly stocked than showier Copadichromis such as Copadichromis borleyi or Copadichromis azureus. Keepers who do seek it out should treat it as a typical open-water utaka: the species needs space above all else. A tank of at least 71–78.5 in (around six feet) in length is the practical minimum for a colony, and longer is meaningfully better — utaka are restless midwater swimmers, and cramped quarters are the single most common mistake made with this group.
Water chemistry must match Lake Malawi: hard, alkaline, and well-buffered. Target a pH of 7.8–8.6 and a temperature of 75–79 °F, consistent with the lake's surface layer. Aim for moderate to high total hardness (GH 10–20°dH is workable) and keep the carbonate hardness high enough to hold pH stable — Malawi buffer mixes or Rift Valley salt blends achieve this easily. Soft or acidic water causes chronic stress and leaves fish prone to the secondary bacterial infections collectively known in the hobby as Malawi bloat. Malawi bloat — often triggered by dietary error or a weakened immune system in fish kept out of their preferred chemistry — is one of the leading killers of captive Malawi cichlids; stable alkaline water and a varied, low-fat diet are the main defences.
Decoration should provide open swimming volume through most of the tank, with a sand substrate and a modest rock arrangement at one or both ends — enough to give males potential bower sites and subordinate fish sight-line breaks without filling the midwater. Elaborate rockwork or dense planting is unnecessary and counterproductive for an inshore-pelagic species. Filtration should be strong and clean: Malawi cichlids are sensitive to dissolved-waste accumulation, and regular large water changes (25–30% weekly) are more effective than oversized filters alone.
For tankmates, choose similarly sized, calm Malawi haplochromines or peacocks (Aulonocara). Avoid aggressive mbuna, which will harass the more passive utaka relentlessly; avoid also fin-nipping species or anything too large that may predate the relatively slender likomae. A single-species colony — one male with two or three females — is a workable approach and removes interspecific competition. Males of the same or closely related utaka species will usually fight, so mixing utaka together requires a very large tank and careful observation.
Breeding in captivity follows the wild pattern. A male in spawning condition develops his darker dress and begins sculpting a sand bower — pushing sand into a low mound on the tank floor, typically away from heavy rock cover. He then displays persistently to females. Spawning is straightforward for an experienced Malawi keeper: the female lays, picks up the eggs, and broods alone for roughly three to four weeks. She should be moved to a quiet holding tank or a breeding trap for the last week of the brooding period if fry survival is a priority, and released fry do best on freshly hatched brine shrimp and fine dry foods. Because Copadichromis likomae is thinly traded, hobbyists who succeed with it contribute meaningfully to maintaining a captive population of a species that is not routinely available.
Conservation
On the IUCN Red List, Copadichromis likomae is assessed as Least Concern (assessed 22 June 2018 by Konings, Kazembe, Makocho and Mailosi; reviewed by Snoeks; an earlier 2006 assessment also returned Least Concern). The justification is that the species is endemic to Lake Malawi but widely distributed there, with an estimated area of occupancy of about 2,435 mi² and extent of occurrence near 49,311 mi², no major widespread threat identified, and occurrence inside Lake Malawi National Park. The one pressure the assessment flags is fishing: unlike many showier haps it is not primarily an ornamental-trade target but is a food fish caught by utaka fishermen, so overfishing by artisanal fishers is named as a potential threat; population trend is recorded as unknown. The fish itself is not currently in trouble. The lake around it, however, is under growing strain — sediment and nutrient loading off deforested catchments, intensifying fishing pressure, climate change, and invasive-species risk are the recognized basin-scale concerns for Lake Malawi/Niassa/Nyasa. As a commercially netted, inshore plankton feeder, Copadichromis likomae sits in exactly the guild most exposed to fishing pressure, even though none of these forces has yet moved it off Least Concern.