The Mexican stoneroller (Campostoma ornatum) is a species of fish native to Arizona and Texas in the United States and parts of adjacent Mexico.

The Mexican stoneroller prefers shallow waters near gravel and stone substrates, and larger adults can be found in sandy-bottomed streams.

Populations are declining rapidly in Rucker Canyon along with San Bernardino Creek, however numbers in Texas and Mexico remain stable.

The Arizona Game and Fish Department gave the species endangered status in 1988, and the Mexican stoneroller remains on the list.

Aquifer pumping, reduction in stream flows, and predation from non-native green sunfish, are all major contributing factors to the decline of the species.

The San Bernardino Ranch has current plans to reintroduce individuals in an attempt to recharge the population, and other projects involve federal habitat preservation.