Cisco are a small slender member of the whitefish group. They have large scales and a bright silver colored body. Like all members of the family they have an adipose fin (small fleshy fin just in front of their tail on their back), no spines in any of the fins, and the belly does not come to a sharp edge or keel. The mouth is moderately sized and terminal (ending at tip of snout) and they have a deeply forked tail. The closely related lake whitefish differs by being deeper bodied and having a smaller sub-terminal (ending below tip of snout) mouth. Additionally lake whitefish attain a much larger size.