Breeding Wallago attu

Breeding notes for Wallago attu, an enormous Asian predatory catfish: an oviparous, migratory river spawner that is wholly unsuitable for home aquaria.

Overview

Wallago attu is a large, voracious predatory catfish of the family Siluridae. FishBase records a maximum length of 240 cm total length, with a common length around 75 cm, distributed across Asia from Pakistan to Vietnam and Indonesia. It mostly hides in holes in river banks and canals, preferring deep, still or slow-flowing water with a mud or silt substrate, and feeds on smaller fish, crustaceans and mollusks.

Conditioning

FishBase describes the species as a pre-monsoon summer breeder, abundant during the warm season. Its reproduction is tied to the monsoon flood cycle, with the natural trigger being rising warm water ahead of the rains.

Spawning Behavior & Trigger

FishBase classifies the species as oviparous, with distinct pairing possibly like other members of the family. In the Mekong it migrates into smaller streams, canals and onto the floodplain during the flood season, then retreats to deep pools in the main river and tributaries when the flood recedes, remaining there until the next inundation.

Common Challenges

Reproduction depends on a large-river flood-migration cycle and on the fish reaching a very large size, neither of which can be provided in an aquarium. Documented reproduction comes from riverine populations and controlled hatchery work rather than home tanks.