Licorice Gourami (Parosphromenus deissneri) Breeding Guide

Breeding Parosphromenus deissneri: a soft acidic blackwater cave spawner, male courtship colours, batch embraces with eggs on the cave ceiling and male-only brood care.

Overview

Parosphromenus deissneri is a tiny labyrinth fish reaching only about 35-40 mm standard length, endemic to Bangka Island, Indonesia. It is a cave spawner that requires very soft, acidic blackwater, tolerating pH as low as 3.0 and up to 6.5 at 22-28 °C, which makes it one of the more demanding aquarium fish to spawn.

Sexing

Males develop elaborate coloration, with the dorsal, anal and caudal fins showing a thin whitish to bluish margin above a black subdistal band, while females are far less colourful. Both sexes change colour with mood, becoming darker when aggressive.

Breeding Setup

Provide small caves or leaf litter in which a pair can spawn, in a quiet, dimly lit tank with very soft acidic water and minimal flow. The species forms only temporary pair bonds, with the male solely responsible for egg and brood care.

Spawning Behavior & Trigger

Males establish territories and use distinctive courtship displays, sometimes assuming a head-down posture and at other times a more horizontal shape. Eggs and milt are released in batches during a series of embraces in which the male wraps its body around the female, and the parents attempt to attach the eggs to the cave ceiling.

Egg & Fry Care

Incubation lasts about 24-36 hours, fry become mobile after 4-6 days and are fully free-swimming a further 3-5 days later, after which parental care ceases once the fry leave the cave. The fry initially swim without direction and may require Paramecium, rotifers or similar as a first food, but are quickly able to accept Artemia nauplii.

Common Challenges

Maintaining the extreme blackwater chemistry stably is the principal difficulty, alongside the small first foods the tiny fry require. Because pair bonds are temporary and only the male tends the brood, a suitable quiet cave and removal of disturbance are important to avoid the spawn being abandoned.