Taxonomy & naming
Leporinus conirostris was described by the Austrian ichthyologist Franz Steindachner in 1875, based on specimens from the Rio Paraíba do Sul basin in Brazil. It belongs to the family Anostomidae — the headstanders — within the order Characiformes, and to the large, diverse genus Leporinus, whose members are recognised across the Neotropics by their elongated, torpedo-shaped bodies, terminal-to-subterminal mouths adapted for grazing, and a habit of feeding at a steep, head-down angle.
The Catalog of Fishes (Eschmeyer, California Academy of Sciences) notes that recent taxonomic work (Panzeri et al., 2026) has proposed moving this species out of Leporinus, via an intermediate placement in Megaleporinus, into a newly recognised genus, Arhinolemur. That revision is recent and not yet the settled consensus reflected across the hobby and most reference material, so this article keeps the long-established combination Leporinus conirostris; readers researching further afield may also encounter the name under Megaleporinus or Arhinolemur. The species epithet conirostris is Latin for "cone-snouted," describing the fish's pointed, conical snout profile.
Morphology
Leporinus conirostris has the classic anostomid build: an elongated, laterally compressed, torpedo-like body with a pointed conical snout and a small, underslung-to-terminal mouth set with incisor-like teeth suited to scraping rather than seizing prey. FishBase records a maximum length of 14.5 in total length, a substantial adult size that new keepers often underestimate from juvenile specimens sold at a few centimetres in the trade.
Colouration typically follows the Leporinus pattern of bold longitudinal or oblique dark bands or stripes over a silvery-to-yellowish base, though exact patterning and intensity vary with age, mood and individual. As in most Leporinus, there is no reliably documented external difference between the sexes.
Habitat
The species is known from the Paraíba do Sul River basin in southeastern Brazil, with its type locality given as the Rio Paraíba near Mendez, Juiz de Fora and Palmeira, and additional records from the Rio Doce and Rio Mucuri systems; it has also been reported from Argentina. These are coastal, subtropical-to-tropical river drainages rather than classic Amazonian blackwater, and conditions across the range vary accordingly.
Aquarium-care sources give a workable water envelope of pH 5.5–7.5 and roughly 73–81 °F, with moderate hardness around 2–10 dGH — mildly acidic to neutral, moderately soft to moderately hard water rather than extreme blackwater conditions. As a grazer, it favours river stretches with rock, wood and marginal vegetation offering plenty of surface area to browse.
Feeding
Leporinus conirostris is an omnivorous grazer, spending much of its time working over submerged wood, rock and leaf litter at its characteristic head-down angle to rasp off algae and biofilm. In the wild this aufwuchs-grazing diet is supplemented with small invertebrates and plant material encountered along the way.
In the aquarium it accepts sinking pellets and a strong vegetable component readily — blanched spinach, zucchini and similar greens are specifically noted as accepted foods — alongside occasional small invertebrate or protein foods. Like many Leporinus, it will also graze on soft-leaved live plants in a planted tank, so aquascaping choices should favour tougher, unpalatable species.
Mating
Detailed courtship behaviour for Leporinus conirostris has not been documented in the sources available for this article. Breeding accounts describe distinct pairs forming and moving into densely weedy areas of the river or aquarium to spawn, consistent with the pairing behaviour reported more broadly across the genus, but specific courtship displays, triggers or external cues are not described.
No reliable external sexual dimorphism is documented for this species; sexes appear similar in colour and body shape, and breeders would need to rely on behavioural cues such as pairing and condition rather than appearance.
Breeding
Leporinus conirostris is an egg-scattering spawner rather than a nest-guarder or mouthbrooder. Reports describe paired fish moving into dense weed growth to spawn, releasing eggs among the vegetation with no parental care afterward — consistent with the broader pattern in Leporinus and Anostomus, where a handful of species have been spawned by hobbyists or farmed commercially but most, including this one, are only occasionally or rarely bred in the home aquarium.
Data on this species' captive spawning is sparse beyond the basic egg-scattering-in-weeds account; anyone attempting it should expect a low-parental-investment strategy and provide dense fine-leaved or fibrous vegetation as a spawning substrate, with eggs and any resulting fry left unguarded and vulnerable to predation by tankmates.
In the aquarium
The single most important thing a keeper needs to know about Leporinus conirostris is that it does not stay small and does not stay polite. FishBase-derived care guidance calls for a spacious tank — commonly cited at 75 US gallons (roughly 75 US gal) and at least 48 inches (47 in) in length — to accommodate an adult approaching 14.5 in, and flags the species as territorial and prone to fin-nipping, a well-known trait across Leporinus and its Anostomus relatives. Tankmates should be chosen for robustness and speed rather than delicacy; slow-moving, long-finned or timid fish are poor companions.
The tank should be tightly lidded, since the species is noted to jump. Décor should include plenty of wood and rock offering grazing surface, since this fish spends much of its time browsing rather than swimming in open water; soft-leaved live plants are likely to be eaten or shredded, so tougher species or artificial planting are safer choices. Water should be kept mildly acidic to neutral (pH 5.5–7.5), moderately soft to moderately hard (2–10 dGH) and warm (73–81 °F), with strong filtration to handle a large, active grazer's bioload.
Conservation
Leporinus conirostris has not been formally assessed by the IUCN Red List; its status is Not Evaluated. This is a common situation for river-restricted Neotropical characins that are neither widely fished commercially nor prominent in the aquarium trade at scale, and it does not imply the species is secure — only that no published assessment currently exists.
As a species restricted to coastal southeastern Brazilian drainages (the Paraíba do Sul, Doce and Mucuri systems), it shares the general pressures facing freshwater fish in this heavily developed, densely populated part of Brazil: damming, water abstraction, sedimentation and habitat degradation from agriculture and urbanisation. In the absence of a targeted assessment, its conservation status should be treated as genuinely unknown rather than assumed safe.