Genus Osmerus is a type of fish that belongs to the family of salmon. There are several synonyms that can be used to refer to this particular species of fish. One of the most common synonyms is rainbow smelt, which reflects the fish's characteristic colors. Other synonyms include Lake Superior cisco and American smelt. The fish can grow up to 9 inches long and is known for its distinctive flavor, which has made it popular in many cuisines around the world. Whether you refer to it as Genus Osmerus or one of its many synonyms, this fish is sure to be a delicious addition to any meal.