Liobagrus reinii (Torrent Catfish) Breeding Guide

Liobagrus reinii is a cool-water Japanese torrent catfish with a polygynous, male-guarded nesting system documented in field studies.

Overview

Liobagrus reinii is the type species of the torrent catfishes, family Amblycipitidae. According to Wikipedia the genus is distributed in the Yangtze River basin, Taiwan, Japan and the Korean Peninsula, and most Liobagrus species grow to about 100 mm SL. It is a cool-water, stream-dwelling catfish, and its common name reflects fast-flowing habitats. Reproduction has been studied in Japanese field populations.

Sexing

Sexing relies mainly on body condition during the breeding season: ripe females become full of eggs. Field studies record spawning females in the size range of roughly 115 to 137 mm SL, while the largest males are the ones most able to court and enfold females.

Spawning Behaviour & Trigger

Field research describes a polygynous mating system in which females distribute their eggs among the nests of several males rather than spawning with a single partner. The largest male is the one that can most frequently approach and enfold the female. Breeding pairs move considerable distances through ditches, paddy fields and creeks, and the timing is set so that larvae appear when plankton and other fish larvae become abundant during the irrigation period.

Egg & Fry Care

A spawning female produces roughly 1,200 to 3,000 developed ovarian eggs. Care of the eggs is by the male: parental males fan and clean the eggs with their pectoral and pelvic fins and behave aggressively in defence of the nest. The spawning site and timing help the resulting larvae avoid predation and feed first on plankton, then on the larvae of other fishes.

Common Challenges

Captive breeding is constrained by the species' need for cool, well-oxygenated, fast-flowing conditions and by the polygynous structure, in which several males and the distances they travel are part of the natural spawning system. Reproducing the migratory movement between habitats and providing multiple nesting males is difficult in a tank, so this remains a specialist undertaking.