Yabby Breeding Guide

Breeding the Australian Yabby (Cherax destructor): a territorial crayfish whose female carries eggs under the abdomen with development of 33.4–42.2 days, plus an invasive-release warning.

Overview

The common Yabby (Cherax destructor) is an Australian parastacid, on average 10–20 cm (4–8 in) long but recorded up to 30 cm (12 in). Wild coloration ranges from black, blue-black or dark brown in clear water to light brown, green-brown or beige in turbid water, and selectively bred forms are a vibrant blue. It is highly territorial, and higher densities increase aggression and lower growth.

Sexing

Females show a reduced growth rate after maturity and are usually smaller than males of the same age; as in other parastacids, sex is confirmed by the position of the genital openings on the legs. A mature pair is needed for spawning.

Breeding Setup

Because the species is highly territorial, low stocking density and many separate hides are essential; crowding raises aggression and lowers weight. A spacious tank with firm, hard, alkaline water and individual refuges lets a berried female isolate herself.

Berried Female & Young

Clutch and brood size and development rate vary widely with genetic and environmental factors. The female carries eggs attached by minute hairs to the underside of her abdomen, and development ranges from 33.4 to 42.2 days, faster at higher temperatures, with no free-swimming larval stage.

Juvenile Care

Juveniles become free-living after leaving the mother and are omnivorous. Given the species' aggression, broods should be given ample space and cover and thinned out as they grow to limit cannibalism.