Taxonomy & naming
Melanotaenia lakamora was described by Gerald R. Allen and Samuel J. Renyaan in 1996, in a paper titled 'Three new species of rainbowfishes (Melanotaeniidae) from the Triton Lakes, Irian Jaya, New Guinea,' published in the journal aqua (Journal of Ichthyology and Aquatic Biology). It was named in the same work as its close neighbours M. kamaka and M. pierucciae, all three drawn from the small cluster of lakes known collectively as the Triton Lakes in what is now the Indonesian province of West Papua. Eschmeyer's Catalog of Fishes records the valid name as Melanotaenia lakamora Allen & Renyaan, 1996; because the species was described in Melanotaenia, where it remains, no parenthetical authority is used.
The holotype (MZB 6205, a male of 2 in SL) and the type series of 75 specimens, 1–2 in SL, came from Lake Lakamora and the adjacent Lake Aiwaso. The specific epithet refers directly to Lake Lakamora, the type locality. The authors interpreted the species as having evolved from a Melanotaenia goldiei-like ancestor and regarded it as most closely allied to the sympatric-region species M. kamaka and M. pierucciae.
Distinguishing M. lakamora from M. kamaka of nearby Lake Kamaka rests mainly on colour pattern, on a modal anal-ray count peaking at 20 (with roughly half of specimens showing 19 or 21), and on the more elongate posterior dorsal and anal rays of males, which in mature fish nearly reach the base of the caudal fin. As is typical across Melanotaenia, the species is far easier to separate by live colour than by overlapping meristic characters.
Morphology
Melanotaenia lakamora is a small rainbowfish, reaching about 2 in in standard length. It has the deep, laterally compressed body and divided dorsal fin characteristic of the genus, with body depth measured at 2.1–3.0 times in standard length and head length 3.3–3.7 times in standard length. Lateral scales number 34–36 and gill rakers about 15. The fin counts recorded in the original description are dorsal spines 4–6, dorsal soft rays 10–13, a single anal spine, and 18–22 anal soft rays.
In life, mature males are an overall mauve, with a silvery-white breast and lower head. Four mid-body scale rows are separated by bright orange stripes, and a broad blackish-to-dark-blue midlateral stripe runs along the flank, most intense between the eye and the pectoral fin and again on the caudal peduncle. The dorsal and anal fins are reddish, sometimes bright red, while the pelvic fins are slightly orange to translucent. Females are plainer: bronze above and whitish below, with a blackish midlateral stripe narrowly edged in orange.
The two sexes differ markedly in shape as well as colour. Males develop a longer first dorsal fin and more elongate, pointed posterior dorsal rays, and they become significantly deeper-bodied with maturity — in specimens larger than 2 in SL, average body depth runs around 42.6% of standard length in males versus about 32.6% in females.
Habitat
The species is confined to two small lakes in the Triton Lakes region of western West Papua, Indonesia, both lying at an altitude of about 689 ft and surrounded by steep forested hills. Lake Lakamora, the type locality, is roughly 4 mi long and 1–2 mi wide, with clear water over a mud bottom and patchy aquatic vegetation. Lake Aiwaso, separated from Lakamora by a ridge about 328 ft high, is roughly circular and about 2 mi across, with slightly turbid water over a limestone-boulder bottom and dense aquatic vegetation. Underwater visibility in the system runs to 10–16 ft, and aggregations of the fish are common in shallow shoreline areas over boulder and weed bottoms.
Water chemistry in these lakes is warm and distinctly alkaline, reflecting the limestone catchment. The original description records Lake Lakamora at 82 °F, pH 8.4, and conductivity 190 µS, and Lake Aiwaso at 84 °F, pH 8.0, and conductivity 60 µS. These are hard, mineral-rich conditions by the standards of many lowland New Guinea rainforest habitats, and prospective keepers should note that this is not a soft-water fish.
The lakes sit at approximately 3°41′S, 134°17′E (Lakamora) and 3°39′S, 134°16′E (Aiwaso). Its confinement to this single small pair of waters is the defining fact of its biology — there is nowhere else it occurs.
Feeding
The diet of Melanotaenia lakamora in the wild was not described in detail in the original account, and direct dietary data are sparse. Inference must therefore rest on the well-documented feeding ecology of the genus: rainbowfishes are opportunistic micro-omnivores that forage in the upper and middle water column, taking small aquatic and terrestrial invertebrates — insect larvae, small crustaceans, and surface-fallen insects — alongside algae and plant material grazed from submerged surfaces. FishBase places the species at an estimated trophic level of about 2.9, consistent with this omnivorous, invertebrate-leaning profile.
The clear, vegetated, boulder-strewn shallows the fish favours would supply exactly this mix of small invertebrate prey and grazable algal growth. In an aquarium setting the species would be expected to behave like its better-studied congeners — accepting good-quality flake and small pellets along with frozen and live foods such as Daphnia, brine shrimp, and Cyclops — though M. lakamora itself is rare in the hobby and detailed captive feeding notes are limited.
Mating
No courtship or spawning behaviour specific to Melanotaenia lakamora was detailed in the original description, so the account here is drawn from the consistent reproductive biology of the genus and noted as such. Rainbowfishes spawn by distinct pairing: a male establishes and defends a small display area and courts females with intensified colour, flaring his fins and flashing the body so that the orange stripes and reddish fins reach maximum saturation. In many Melanotaenia a pale flickering 'courtship band' flashes along the head and nape of a displaying male, and display is generally strongest in the morning hours.
The marked sexual dimorphism of M. lakamora — deeper-bodied, brighter, longer-finned males — is the visible product of this display-driven mating system, in which females choose among competing, ornamented males. Males are expected to display hardest in the presence of rivals, so the fish is probably at its most colourful when several males are kept together rather than singly.
Breeding
Breeding behaviour was not documented in the 1996 description, and verified captive-breeding accounts for this rarely kept species are scarce; what follows reflects the general, well-established breeding biology of Melanotaenia and should be read as genus-level expectation rather than species-specific record.
Rainbowfishes of this genus are egg-scattering plant spawners with no parental care. Conditioned pairs deposit small numbers of adhesive eggs at a time among fine-leaved vegetation or, in captivity, over synthetic spawning mops, the eggs hanging from the spawning medium by fine filaments. Spawning is typically protracted, a female releasing a few eggs over many days rather than a single large clutch. Adults readily eat their own eggs and fry, so breeders harvest the eggs or mops to a separate rearing container. Fry are tiny and require very small first foods — infusoria, rotifers, or commercial liquid fry food — before graduating to newly hatched brine shrimp. Given the species' restricted wild range, any captive population is of conservation interest, but established hobby strains of M. lakamora are uncommon.
In the aquarium
Melanotaenia lakamora is seldom encountered in the aquarium trade; the small amount of live stock that reached hobbyists traces to collector Heiko Bleher, who gathered the fish in June 1995 (with Paola Pierucci and Patrick de Rham) around the time of the type material. As a result, husbandry information specific to this species is limited, and most guidance is extrapolated from better-known small rainbowfishes.
What the habitat data make clear is that this is a warm, hard-water, alkaline-adapted fish: its native lakes sit near 82–84 °F with pH around 8.0–8.4 over limestone substrates. Keepers should therefore aim for neutral-to-alkaline, moderately hard water and warm temperatures rather than the soft, acidic conditions sometimes assumed for New Guinea fishes. Like its relatives it would be expected to do best as an active, peaceful schooling fish kept in a group, in a tank offering open swimming space alongside planted and structured areas that echo the weed-and-boulder shallows it favours in the wild.
Conservation
Melanotaenia lakamora is assessed as Endangered (EN) on the IUCN Red List, under criteria B1ac(i), with the assessment dated 5 December 2019 and published in the 2020 assessment cycle. The listing reflects the species' extremely restricted extent of occurrence: it is confined to just two small Triton Lakes, Lakamora and Aiwaso, a range so narrow that any localized disturbance — habitat alteration, water-quality change, or the introduction of non-native fishes — could affect a large fraction of the global population at once.
A narrowly endemic species in a single small lake pair has essentially no buffer against such pressures: there is no large outlying population to absorb local declines, the vulnerability the IUCN's range-based B1 criterion is built to capture. The species has not been evaluated under CITES or CMS.
Because M. lakamora is barely present in the aquarium hobby, the captive-breeding safety net that cushions more popular relatives like M. boesemani does not really exist for it. Maintaining and documenting any captive stock, and protecting the two lakes themselves from introduced fishes and habitat degradation, are therefore the central conservation priorities for this species.