Julidochromis marlieri Breeding Guide

How to breed Julidochromis marlieri: forming a bonded pair, a rocky cave setup, biparental defence of the eggs, and growing on the fry.

Overview

Julidochromis marlieri is a rock-dwelling cichlid endemic to Lake Tanganyika, reaching up to about 15 cm. It is a cave (crevice) spawner that forms strong, long-lasting pair bonds and defends a rocky territory. Both parents take part in raising the brood, which makes it a rewarding biparental breeder.

Sexing

Sexing is difficult. Unusually, adult females are larger than males. Males have more extended, pointed genital papillae, which can help confirm sex at close range during conditioning.

Conditioning

The most reliable route to a pair is to raise a group of juveniles together and allow them to pair off naturally; this may take a year or more. Once a stable pair forms, the rest of the group is usually best removed.

Breeding Setup

Provide piles of rocks arranged to form caves in a tank of at least about 120 cm in length. Maintain hard, alkaline Tanganyikan conditions: temperature around 25-27 C (about 77-80 F) and pH 8.2-9.0. The pair spawns very secretively inside a cave.

Spawning Behavior & Trigger

Spawning takes place out of sight within a cave. The female lays up to 100 eggs (usually fewer) on the wall or roof of the cave. The female tends the eggs while the male guards the area around the cave; during the period she is caring for fry the female becomes the dominant fish.

Egg & Fry Care

Fry are large enough to take brine shrimp nauplii from the time they become free-swimming. They can remain with the parents until around 2.5 cm (about 1 inch) in length, at which point they should be removed. Because the pair bonds for life, an established pair often breeds repeatedly with successive broods tolerated nearby.

Common Challenges

Forming a compatible pair is the main hurdle and can take a long time. Insufficient rockwork or cramped quarters undermine the pair's sense of a defensible territory and can trigger aggression.