As a desert park, only a few places in Big Bend support fish. The Rio Grande and its two tributaries, Tornillo and Terlingua Creeks, are the only locations that fish inhabit. Although catfish (blue, channel, and flathead) are commonly caught in the Rio Grande, most of the park's 40 species of fish are minnow-sized. One of the most famous of these is the endangered Big Bend Gambusia, or Big Bend Mosquitofish (Gambusia Gaigei) which is found only within one tiny spring-fed pond near Rio Grande Village. This is the smallest geographic range of any known vertebrate.