The bigmouth buffalo (Ictiobus cyprinellus) also known as the gourd head, redmouth buffalo, buffalo fish, bernard buffalo, roundhead, or brown buffalo, is a large species of the Catostomidae or "sucker" carp family.
The bigmouth buffalo is a dull brownish olive color with dusky fins. Like other suckers it has a long dorsal fin, but unlike others it has a large oblique and terminal mouth. It is the largest of the buffalo fish and reaches a length of more than 4 ft (1.2 m) and 65 lb (29 kg) in weight.
It is distributed from the Red River of the North, Manitoba, Canada, and North Dakota, United States, to the Ohio River and south in the Mississippi River system to Texas and Alabama in the United States. It lives in sluggish areas of large rivers and shallow lakes and streams.