Auchenipterichthys coracoideus · Midnight Catfish

Overview

A retiring wood-associated catfish, Auchenipterichthys coracoideus shelters by day and moves into open water to feed at night. Tangled roots, plants, and hollow timber provide refuge, and subdued aquarium lighting encourages more visible activity.

Distribution & habitat

Described from Iquitos in northeastern Peru, it is considered widespread through the upper and central Peruvian–Brazilian Amazon and the Essequibo drainage in Brazil and Guyana. It uses turbid rivers, tributaries, and flooded areas, sheltering within submerged wood or vegetation during daylight.

Aquarium setup

Provide numerous retreats, especially tangled driftwood and densely planted patches. Keep current low and lighting subdued to encourage the fish to leave shelter.

Diet & feeding

Insects and their larvae make up nearly all of its natural diet. Offer live or frozen bloodworms, small earthworms, and similar food; most individuals learn to accept sinking preparations. Feed after lights-out initially to match nocturnal foraging. Settled fish may later emerge at ordinary feeding time.

Behaviour & compatibility

Peaceful and shy, it may nevertheless eat very small fish at night. Comparable nonaggressive characins, cichlids, and suitable armored catfish are candidates. It shows no aggression toward its own kind and appears comfortable either alone or in a group.

Sexual dimorphism

Mature males develop a hooklike extension at the anal-fin tip used in mating. Breeding males also show a greatly elongated dorsal spine.

Breeding

Aquarium breeding has occurred. The male uses its modified anal fin for internal fertilization, after which the female lays eggs onto the substrate. Parental guarding has not been observed. Females apparently retain sperm, as fertile eggs have been produced without a male present.

Notes

It has frequently been confused with a similar species. Anal-fin ray counts and provenance help distinguish them, with the extended spine of breeding males providing another clue. Trade names alone are unreliable.