Breeding the Mosaic Cherax (Cherax boesemani)

Breeding the West Papuan Cherax boesemani and its 'Mosaic' colour form: a Parastacidae crayfish that reproduces as a berried female with direct development.

Overview

Cherax boesemani (Lukhaup & Pekny, 2008) is a freshwater crayfish from the Ajamaru Lakes and Ajamaru River of the Kais River drainage on the Vogelkop (Kepala Burung) Peninsula, West Papua, Indonesia. Carapace colours range across blues, reds and oranges, and selective lines such as Blue Moon and Supernova exist; the 'Mosaic' form shows mottled orange and blue. Adults reach about 13-15 cm. The IUCN lists it as Data Deficient. It reproduces as a berried female with direct development.

Sexing

Determine sex from the genital openings on the underside: males show paired papillae at the base of the last walking legs, females openings at an earlier pair. Mature males tend to grow heavier claws, but the ventral check is the reliable method, since colour forms do not indicate sex.

Conditioning

Stable parameters and a varied omnivorous diet bring this larger Cherax into breeding condition. As documented for the genus, fertilised eggs develop inside the female for roughly four to six weeks before transferring to the outside of her body and resting on the tail.

Breeding Setup

Given the adult size and aggression, a large tank with numerous caves is needed to space the pair and shelter a berried or moulting female. The pair grapples during mating, the male deposits sperm, and the female then carries the eggs on her tail until hatching.

Berried Female & Young

Eggs and hatched juveniles are held beneath the female's abdomen, and the young emerge as miniature crayfish because development is direct. They stay with the mother before dispersing; moving the female once juveniles release reduces predation losses.

Common Challenges

Strong aggression and cannibalism of soft, freshly moulted juveniles are the main difficulties; ample cover and multiple feeding points mitigate them. The species is unsafe with fish, shrimp and plants and should be kept in a species-only tank.