Bonneville Cisco (Prosopium gemmiferum)

The Bonneville cisco is a small, silvery salmonid with a streamlined, laterally compressed body typical of the Prosopium genus. Adults typically reach 6 to 10 inches in length, though some individuals may grow slightly larger. The body is covered with large, easily detached scales and displays a bright silver coloration on the sides with a darker blue-gray to olive back. The belly is white or pale silver. The head is relatively small with a blunt snout and a small, subterminal mouth positioned slightly below the tip of the snout. The adipose fin, characteristic of salmonids, is present between the dorsal and caudal fins. During spawning season, males may develop slight tubercles on their scales and fins. The lateral line is complete and nearly straight. Distinguishing this species from other ciscoes requires careful attention to gill raker counts and body proportions, as visual differences among Prosopium species can be subtle.