Croaking Gourami Breeding Guide

How to breed Trichopsis vittata, a bubble-nesting labyrinth fish whose males build surface nests and the female emits purring sounds during courtship.

Overview

Trichopsis vittata is a small labyrinth fish of the family Osphronemidae, native to still waters of Southeast Asia including Thailand and parts of the Sunda region. Both sexes produce an audible croaking or grunting noise generated by specialised modifications of the pectoral fins, which is used during breeding displays and in dominance interactions between males. It is a bubble nester of intermediate breeding difficulty.

Sexing

Males are larger and display extended rays in the pelvic, dorsal, anal and caudal fins. Females can be identified by directing a strong light behind the body, which reveals the ovaries visible below the swim bladder. Mature females also appear fuller-bodied when in condition.

Conditioning

Condition the chosen pair on varied live and frozen foods. Soft water combined with a slightly elevated temperature helps induce reproductive behaviour. Maintaining the broader water values within the species range of 22-28 °C and pH 6.0-7.5 keeps the fish in spawning condition.

Breeding Setup

Use a separate tank with the tightest-fitting cover possible; some breeders use plastic wrap to trap a layer of warm, humid air above the surface, which is essential for development of the labyrinth organ in the fry. Lowering the water to around 20 cm with minimal circulation and providing surface vegetation or a floating overhang gives the male a site for the nest.

Spawning Behavior & Trigger

The male constructs a bubble nest of air bubbles and mucus within surface plants, under an overhang, or in a cavity. During courtship he displays with his elongated fins while the receptive female approaches vertically, emitting a series of purring sounds. Spawning takes place beneath the nest in the typical osphronemid embrace, with the male wrapping around the female; he then collects the eggs and spits them into the nest, often adding more bubbles.

Egg & Fry Care

A typical spawn ranges from around 1 to 200 eggs, with large females sometimes laying more than 200. Eggs normally hatch within about 48 hours, and the fry remain in the nest for a further 3-4 days until the yolk sac is absorbed. Offer infusoria-grade foods for the first few days, then progress to microworm and Artemia nauplii. Carry out small, regular water changes rather than large, infrequent ones.

Common Challenges

The humid air layer above the nest must be preserved or labyrinth organ development is impaired. Although the female is often tolerated and may help defend the nest, removing her after spawning reduces the risk of egg predation, and the male should be removed once the fry are free-swimming.