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.

[4][5] Koonacs are endemic to the southwest of Western Australia, in wetlands, permanent and seasonal waterways, and farm dams.

[6] Although they are rated as "least concern" on the IUCN redlist, local populations may be under threat by introduced eastern states yabbies such as Cherax destructor and Cherax albidus through competition for food and habitat.

[1][7] Although catching koonacs is not seasonally restricted, fishing for marron is.