Taxonomy & naming
Kolpotocheirodon theloura was described by Luiz Roberto Malabarba and Stanley Howard Weitzman in 2000. The species is placed in the genus Kolpotocheirodon, which was erected in the same publication to accommodate it; the genus is monotypic or nearly so, representing a distinct lineage within the family Characidae as recognised by Eschmeyer's Catalog of Fishes.
The specific epithet theloura derives from Greek roots (thele, nipple, and oura, tail), likely referring to a morphological feature of the caudal region noted in the original description. The authority is given without parentheses, as the species was described directly in Kolpotocheirodon. It belongs to a broad assemblage of small South American tetras whose interrelationships and subfamilial placement continue to be refined by molecular and morphological studies.
Morphology
Kolpotocheirodon theloura is a small characin reaching less than 2 in standard length. Like many characids from Amazonian tributaries, it is a slender, laterally compressed fish with the typical tetra bauplan: a single dorsal fin, a small adipose fin, forked caudal fin, and the complete lateral line typical of the family.
Beyond the general body plan, detailed meristic and morphometric data from the original description define the species, including features of the caudal region that give rise to the specific epithet. Colouration in life is not well documented in the published hobbyist literature; preserved specimens of small characins are often plain silvery or lightly pigmented, and live colour in this species remains poorly characterised.
Habitat
The species is known from the Ucayali drainage in Peru, a major western tributary of the Amazon. The Ucayali and its tributaries drain the eastern Andean foothills and lowland forest, carrying white, black, and clear waters depending on the sub-catchment. Small tetras in this system typically inhabit densely vegetated margins, flooded forest, and slow-moving or still side waters with organic substrate and leaf litter.
No specific habitat data for K. theloura have been published in the accessible hobbyist literature, and the species appears to have been collected infrequently since its original description. Water conditions for the Ucayali drainage are broadly warm and can range from soft and acidic in forest streams to moderately mineralised in main-channel waters.
Feeding
No specific feeding studies have been published for Kolpotocheirodon theloura. Small characins of similar size and habitat in the Ucayali drainage are generally opportunistic microcarnivores or omnivores, taking small invertebrates, zooplankton, insect larvae, and organic detritus in the wild.
In an aquarium context, a species of this size and family would be expected to accept small prepared foods such as fine-grade flake or micro-pellets, supplemented by small live or frozen invertebrates such as Artemia nauplii, Daphnia, and micro-worms. Data sparse for this species specifically.
Mating
No mating observations specific to Kolpotocheirodon theloura have been published. The species is assumed to follow the typical Characidae reproductive strategy of egg-scattering with no parental care, which is the dominant mode across the family.
In this mode, males court females with brief pursuit and parallel swimming before a spawning rush over fine-leaved vegetation or substrate. Eggs are released freely into the water column or among plant material and receive no guarding from either parent. Spawning in the wild likely correlates with seasonal water-level and rainfall cycles, as is common among Amazonian characins.
Breeding
No captive breeding accounts for Kolpotocheirodon theloura are known in the published hobbyist literature, reflecting its near-absence from the aquarium trade. Based on the family pattern, this species would be expected to scatter small, non-adhesive to lightly adhesive eggs among fine-leaved plants or spawning mops, with eggs hatching after a few days at tropical temperatures.
Breeding the species in captivity, should it become available, would likely follow protocols used for similar small Amazonian tetras: a separate, dimly lit breeding tank with soft, slightly acidic water, fine-leaved plants or a spawning mop, and removal of adults after spawning to prevent egg predation. Fry would require infusoria or commercial liquid fry food as first foods before graduating to newly hatched brine shrimp.
In the aquarium
Kolpotocheirodon theloura is essentially unknown in the aquarium hobby and is not commercially available through normal trade channels. Hobbyist biotope data are absent, and no care accounts are on record.
If it were to become available, the general husbandry guidelines for small, delicate Amazonian tetras would apply: a well-planted, dimly lit biotope aquarium with soft, warm, slightly acidic to neutral water, tankmates of comparable size and peaceful temperament, and a varied diet of small prepared and live foods. The scarcity of field and aquarium data means that any care recommendations beyond these general principles would be speculative.
Conservation
Kolpotocheirodon theloura has not been formally assessed by the IUCN Red List and is recorded as Not Evaluated (NE). This is common for recently described, rarely collected Amazonian small tetras: the information required for a formal assessment — range size, population trends, and documented threats — has not been compiled.
The Ucayali drainage in Peru faces ongoing pressures from deforestation, agriculture, and hydrocarbon extraction in parts of its catchment. For a species known from few specimens and a restricted or at least poorly documented distribution, these regional trends represent a potential concern, though no species-specific data on population status exist. Collection for the ornamental trade is not a documented factor, given its absence from commerce.