Cherax preissii, the common koonac, is a Western Australian freshwater crustacean in the Parastacidae family.

Its common name of "koonac" is also applied to another Western Australian Cherax species of crustacean C. glaber, the "glossy koonac", which is restricted to a much smaller region of WA.

Koonacs can grow up to 20 cm and may be coloured black and red, dark brown, or bluish black. They have broad, serrated claws and four keels on the head, two of which are prominent.

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