Family: Cyprinodontidae, Characidae, Poeciliidae
Genus: Cyprinodon, Astyanax, Gambusia
This category of fish is full of unique and otherwise difficult to classify species. Excluding the gambusia, which is categorized here due to its status as extinct, each is the sole confirmed member of its family within Amistad NRA. This makes them relatively easy to identify and pick out in a crowd (If they you can find them at all).
Studies have suggested that this fish may be one of the most chemically and physically resistant fish species in freshwater. The sheepshead minnow is often found flourishing in systems that would normally be difficult to inhabit for other fish, if they are inhabitable at all.
Sheepshead minnows have a deep body, with dark triangular blotches running from the dorsal side. This minnow has a truncate caudal fin (flat ended) and a single dorsal fin.
The mexican tetra is an opportunistic insectivore that can become invasive in most systems where it finds a niche. Historically, these cold intolerant fish were known to migrate through the Pecos and Rio Grande until the severe winters would wipe them out. With the recent additions of dams such as Amistad, these patterns have ended. Due to bait fish introductions, they are commonly found across much of Texas.
Outside of Catfish, only the mexican tetra possesses an adipose fin. It also has vibrant red fins and dark stripe on caudal fin base, and a very blunt snout.
Amistad Gambusia (Extinct)
In 1968 the amistad gambusia became extinct in the wild as a result of the inundation of Goodenough Springs by Amistad Reservoir. Up until the 1980’s populations of this fish were kept at the University of Texas at Austin and the U.S. Fish and Wildlife Service endangered species culture facility, but both populations were eliminated due to contamination by the western mosquitofish.
Identified by its unique orange or yellow body and midlateral stripe that is often present. It usually shows up faintly red or orange.
Last updated: February 12, 2019