This sucker is a common native fish in the lower Merced and Tuolumne river systems. Although it is found abundantly in Yosemite Valley, it is probably not native above the high waterfalls. Sacramento suckers are found in Tenaya lake where supposedly they were introduced along with trout during early fish planting operations.

The sucker may be distinguished from all other fishes of Yosemite by its yellow-brown coloration and the disc-like protuberance of the upper lip which is flattened and protruding.

In the Merced river, they reproduce profusely in the spring. The eggs hatch in a week or so. The young live in the shallow quiet pools, and swim in dense schools at various water levels. During this stage they feed mainly upon plankton (minute life existing in the water).

The adults, which grow to lengths of over a foot, are more or less solitary inhabitants of the deeper pools of the Merced River. At almost any time during the day they may be seen leisurely mouthing their way over the rock surfaces in search of food. They are primarily bottom feeders and mainly herbivorous in food habits. In the spring of 1947, Assistant Park Naturalist Robert N. McIntyre caught a 19 inch sucker which weighed three and a half pounds.

They are occasionally taken by bait fishermen using worms or doughballs but they are usually discarded. Although it contains many small bones, the flesh of the sucker is flavorful, firm, and flaky when the fish are caught in cold mountain water. This fish is generally frowned upon by trout fishermen who accuse it of eating trout eggs or disturbing the stream bottom in which trout eggs have been laid. Although occasionally guilty of these charges, suckers are believed to be of little harm and the young suckers undoubtedly provide food for trout, which more than compensates for any damage done. The Sacramento sucker, in Yosemite, should not be destroyed but rather they should be preserved as part of the native fish fauna of the park.