The ruffe is a small member of the perch family that is native to central and eastern Europe. It was introduced in Minnesota, probably in tanker ballast water, around 1985, and is spreading to other rivers and bays around Lake Superior. The ruffe has not been found in Iowa to date, a trend that is hoped will continue. In infested areas, the ruffe has caused a serious impact on populations of yellow perch, emerald shiners, and other forage fish.

The ruffe's ability to displace other species in newly invaded areas is due to its high reproductive rate, its feeding efficiency, and spiny characteristics that may discourage would-be predators such as walleye and pike.

Ruffe grow rapidly and can reproduce in their first year. Females can lay between 45,000 and 90,000 eggs each year. Ruffe are primarily bottom feeders, preferring dark environments where they can hide from predators. Ruffe rarely grow bigger than 5 inches, although the sharp spines on their gill covers, dorsal and anal fins make them difficult for larger fishes to eat.

They are most likely spread through transport in livewells, bilgewater, bait buckets, and in the ballast water of Great Lakes freighters.

If you think you have caught a Ruffe, contact your local Iowa DNR fisheries biologist immediately.