Percopsis omiscomaycus also known as the trout-perch, the grounder or the sand minnow, is one of two species in the family Percopsidae. They are freshwater fish that prefer clear to slightly turbid water. They are most often seen washed up on beaches and are rarely seen alive or correctly identified. They are found in rivers and lakes throughout North America. Its name comes from the Greek root words perc, meaning perch and opsi meaning appearance. The species name omiscomaycus is thought to be derived from a Native American word meaning trout. The trout-perch possess characteristics similar to both the trout and the perch. They are an important source of food for many predator fish such as walleye, northern pike, and lake trout. They are a generally small fish found in deep waters by day, but which migrate to shallower waters at night. They are not a major human fishery, but are occasionally used as a bait fish.