Taxonomy & naming
Lebiasina melanoguttata was described by Netto-Ferreira in 2012. The valid name, as governed by the Catalog of Fishes (Eschmeyer, CAS), is Lebiasina melanoguttata Netto-Ferreira, 2012. As a species described in 2012, it represents one of the more recently formalised members of the genus, and detailed synonymy or subsequent revision is not recorded in the available literature.
The genus Lebiasina belongs to the family Lebiasinidae, the pencilfish-and-splashing-tetra lineage within the order Characiformes. Lebiasinidae is a neotropical family distinct from the broader Characidae, and its members occupy a range of stream and forest-pool habitats across South America. Within Lebiasina, species are distinguished by body proportions, scalation, and colour pattern — the arrangement of spots or bands on the flanks being particularly diagnostic. The formal description of L. melanoguttata in 2012 reflects ongoing ichthyological survey work that continues to reveal new species from the rivers and forest streams of South America.
Morphology
Lebiasina melanoguttata is a small, moderately slender fish with the elongated, roughly cylindrical profile typical of the genus. Like other lebiasinids it is more pencil-like in shape than the deep-bodied characins commonly seen in the hobby, with a streamlined form suited to navigating leaf litter and root tangles in forest streams. Precise size data for this species are not available in the sources consulted; members of the genus typically reach around 2–3 in standard length, and L. melanoguttata is assumed to fall within that range pending publication of detailed morphometric data.
The specific epithet melanoguttata — from the Greek melano- (black or dark) and the Latin guttata (spotted) — describes the defining feature of the colour pattern: dark spots distributed along the flanks. These are set against a lighter, typically warm ground colour, and the contrast is most apparent in well-fed, settled specimens under natural or warmer aquarium lighting. Fins are likely clear to faintly pigmented in keeping with the genus. Like most lebiasinids, the species lacks an adipose fin, and the mouth is relatively small and terminal.
Habitat
Members of the genus Lebiasina inhabit small forest streams, blackwater tributaries, and marginal pool habitats in the river drainages of northern and western South America, typically at elevations from lowland floodplains up into foothill drainages. These environments are characterised by soft, acidic water stained by decomposing leaf litter and tannins from the surrounding forest, low mineral content, and dense cover from submerged roots, aquatic macrophytes, and fallen debris.
The precise type locality and known range of Lebiasina melanoguttata were not recovered in the sources consulted for this article. Based on its congeners and the biogeographic context of its description, it is expected to occur in a similar forest-stream habitat within the neotropical region of South America. Water conditions in such habitats are typically soft and acidic — temperatures in the range of 72–79 °F, pH from around 4.5 to 6.5, and very low conductivity — but these figures should be treated as indicative of the genus rather than confirmed for this species specifically until the original description or subsequent field surveys are consulted.
Feeding
Lebiasina melanoguttata is presumed to be an omnivore in the manner of its congeners, foraging among leaf litter, plant surfaces, and the water column for small invertebrates and organic matter. The natural diet of Lebiasina species typically includes aquatic insect larvae, microcrustaceans, small worms, and similar invertebrate prey encountered while picking through substrate and vegetation. Opportunistic consumption of algal films and particulate organic matter supplements the animal-protein component.
In the aquarium the species is expected to accept small-grade prepared foods — micro-pellets and fine flake — along with live and frozen foods such as Daphnia, baby brine shrimp, and Cyclops. Feeding small amounts two or three times daily suits the foraging style of the genus better than a single large daily meal. As a small, peaceful fish it should not be housed with boisterous or significantly larger species that would outcompete it at feeding time.
Mating
Lebiasina melanoguttata is an egg-scattering open spawner following the pattern typical for the genus, with no parental care of eggs or fry. Males are expected to pursue ripe females through vegetation and leaf litter, with spawning occurring in short, active bouts. Eggs are scattered or deposited adhesively among fine-leaved plants, Java moss, or leaf litter, and the adults take no further interest in them.
Courtship behaviour in Lebiasina species is generally brief compared with the more elaborate displays seen in related pencilfish genera. Spawning is stimulated by stable, warm, soft, and acidic water conditions and the presence of fine-leaved vegetation or spawning substrate. There is no pair bond and no post-spawning association between the sexes.
Breeding
Breeding Lebiasina melanoguttata follows the general pattern of the genus: eggs are scattered or deposited adhesively among fine-leaved vegetation or spawning mops and are left entirely without parental care. The adults are likely to consume eggs if left in the spawning container, so breeders should either remove the adults promptly after spawning or use a spawning medium from which eggs can be easily harvested.
Incubation times are not specifically documented for this species in the available literature. By analogy with closely related Lebiasina species and similar small tropical characins in warm, soft water, incubation is expected to take a few days to a week at around 75–79 °F. Fry are small at hatching and will require very fine first foods — infusoria, rotifers, or commercial liquid fry food — before moving on to newly hatched brine shrimp nauplii and finely powdered flake. Detailed captive-breeding data for L. melanoguttata remain sparse given its recent description and rarity in the hobby.
In the aquarium
Lebiasina melanoguttata is not an established aquarium fish and is unlikely to be encountered in the trade outside specialist collections. Should it become available, its care requirements are expected to follow those of the genus broadly: a planted aquarium with warm, soft, acidic water (around 72–79 °F, pH 5.0–6.5), low light or tannin-stained conditions to replicate the natural forest-stream habitat, and a substrate of fine sand or leaf litter. Dark substrate and subdued lighting bring out the dark spot patterning and produce calmer, more confidently behaved fish.
The species is peaceful and best kept in groups with similarly sized, non-aggressive tankmates. Other small lebiasinids, dwarf pencilfish, small South American tetras, and small Corydoras make suitable companions. At the modest size typical of the genus it should not be housed with significantly larger or predatory fish. Water quality and stability are the primary care concerns — regular partial water changes with well-conditioned, soft water are essential. Feeding poses no special difficulty for an owner experienced with similar soft-water tetras and pencilfish.
Conservation
Lebiasina melanoguttata has not been assessed by the IUCN Red List. As a species described only in 2012, it has not yet been subject to a formal conservation evaluation, and its population size, distribution, and trend are not documented in the available literature.
The forest streams and small tributaries that Lebiasinidae species inhabit across South America face ongoing pressure from deforestation, agricultural conversion, and water extraction. Narrowly distributed species in this family may be particularly vulnerable to localised habitat loss. The absence of an IUCN assessment should not be read as an indication of security; it reflects the limited scientific attention directed at this recently described and little-studied species. Until the type locality and full range of L. melanoguttata are well documented and a formal assessment conducted, its conservation status must be treated as unknown.