Taxonomy & naming
Fadly Y. Tantu and J. Nilawati described Telmatherina albolabiosa in 2008, in Wallacea, Journal of Biodiversity, from material collected in Lake Matano, South Sulawesi. The genus sits in the family Telmatherinidae, the sailfin silversides, within the order Atheriniformes — the same assemblage that holds the marine silversides and, more distantly, the rainbowfishes. Eschmeyer's Catalog of Fishes governs the valid name: Telmatherina albolabiosa Tantu & Nilawati, 2008.
The sailfin silversides of the Malili lake system in central Sulawesi — Lake Matano being the largest and deepest — are a textbook freshwater species flock: closely related fishes that diversified in place within one isolated basin. T. albolabiosa belongs to that Matano radiation. Its describers separated it from its congeners chiefly on the form of the mouth and lips and on several head proportions, not on the meristic (fin-ray and scale) counts, which overlap broadly across the lake's Telmatherina.
Morphology
Telmatherina albolabiosa is a small, slender, benthopelagic fish. The original description gives a maximum size of about 3 in standard length in males and unsexed specimens and roughly 2.5 in standard length in females, making it a typically small sailfin silverside. The body is elongate, with the two separate dorsal fins characteristic of the genus and family — a short spinous first dorsal followed by a soft-rayed second dorsal. Reported fin counts are 5 to 6 dorsal spines, 8 to 9 dorsal soft rays, a single anal spine, and 11 to 12 anal soft rays.
The diagnostic feature, and the source of the name, is the mouth. T. albolabiosa has a terminal mouth bearing thick, protrusible, milky-white lips — a trait that sets it apart from every other Lake Matano congener. The describers also noted a comparatively long head (about 35 to 39 percent of standard length), a long snout (about 11 to 13 percent), and a narrow interorbital (about 7 to 9 percent). Published notes on live coloration are thin; as in many Telmatherina, colour and fin development are probably most pronounced in males.
Habitat
The species is endemic to Lake Matano in South Sulawesi (Celebes), Indonesia, and known from nowhere else. Matano is an ancient, deep, clear tectonic lake at the head of the Malili system, and its long isolation is the setting in which the local Telmatherina flock evolved. T. albolabiosa is a tropical freshwater fish, benthopelagic in habit.
Within the lake it keeps to rocky habitat rather than the vegetated shorelines, and has been reported in small groups of two or three. Surveys of Telmatherina across Matano have contrasted the assemblages of vegetated and rocky shores; T. albolabiosa falls on the rocky side of that line. Water-chemistry figures for its microhabitat are thin in the cached sources. Matano as a whole is a clear, well-oxygenated, mineral-influenced tropical lake, but precise temperature, pH and hardness values for the species are not documented here and are best treated as data-sparse.
Feeding
An estimated trophic level near 3.1 marks T. albolabiosa as a small, partly carnivorous fish that takes invertebrate prey rather than feeding mainly on plants. Sailfin silversides generally are micro-predators and opportunists, gleaning small aquatic invertebrates, insect larvae, and zooplankton from the water column and from substrate surfaces.
The thick, protrusible lips that define the species point to a feeding mode tied to the rocky substrate — such lips often go with picking or scraping prey off hard surfaces — but the cached sources carry no published diet analysis. Lacking species-specific gut-content data, its feeding ecology can only be sketched from the genus and the rocky shore it occupies, with the lip morphology a likely functional specialization rather than a confirmed dietary one.
Mating
The cached sources hold no species-specific account of courtship in Telmatherina albolabiosa, so this section stays general. Across the Matano sailfin silversides, males are usually the more ornamented sex and engage in visual display and competition; several Telmatherina are known for elaborate male colour and fin signalling in courtship and in male-male contests.
Since T. albolabiosa turns up in small groups on rocky habitat, males plausibly display to females and rivals over localized sites on the rocky shore, as is common in the genus. But the specifics — display posture, courtship coloration, mate choice, any pairing — are not documented for the species and should not be invented. The mating biology here is data-sparse.
Breeding
No species-specific breeding account for Telmatherina albolabiosa appears in the cached sources, and with the fish effectively absent from the trade there are no hobbyist spawning reports to lean on. Telmatherina sailfin silversides are generally egg-layers that deposit adhesive eggs, as atheriniform fishes do, but clutch size, spawning substrate, incubation period, and fry development for this species are not documented here.
What can be said is that a narrow endemic of one ancient lake reproduces entirely within that confined water, and any captive breeding would have to rebuild conditions from the rocky-shore habitat. Past that, the details are data-sparse; specifying egg counts or timelines the sources don't support would be guesswork.
In the aquarium
You will not find this fish in the hobby. No dedicated care or breeding profile for the species turned up, and the Lake Matano Telmatherina endemics are largely absent from the ornamental trade. Any husbandry note here is extrapolated from the genus and from the few sailfin silversides that are occasionally kept — read it with that caveat.
Sailfin silversides are active, schooling, surface-and-midwater fishes that want clear, well-oxygenated, stable water and open swimming room, in keeping with their origin in clear ancient lakes. A keeper attempting this or a related Telmatherina would aim for a clear, hard-bottomed, rocky-shore setup with strong water quality and a small group, since wild fish have been seen in twos and threes. No verified aquarium temperature, pH, or hardness ranges exist for T. albolabiosa in the cached sources, so specific captive parameters are left unstated rather than guessed.
Conservation
Telmatherina albolabiosa is assessed as Data Deficient (DD) on the IUCN Red List, in an assessment dated 2018. The Data Deficient category means that there is not enough information on the species' distribution, abundance, or trends to assign it to a threat category — it is not a statement that the species is secure.
For a fish confined to one small lake, a Data Deficient listing is a flag for concern, not reassurance. T. albolabiosa is a narrow endemic of Lake Matano with no outlying population, which leaves it little buffer against habitat change. The Malili sailfin silversides as a whole face documented pressure from introduced fishes and from changes to their lake systems, and single-basin species are exactly the kind such pressure can hit fast. The core conservation fact is the tiny, single-lake range; the chief gap is solid information on population size and trend.