Other Fishes

Other Fishes
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 listed in this category because it is extinct, each is the sole confirmed member of its family within Amistad National Recreation Area. This makes them relatively easy to identify and pick out in a crowd (If you can find them at all).

 

Sheepshead minnow (Cyprinodon variegatus)

Chad Thomas

Sheepshead minnow
(Cyprinodon variegatus)

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 for fish to inhabit, 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 (flat-ended) caudal fin and a single dorsal fin.

 

Mexican tetra (Astyanax mexicanus)

Chad Thomas

Mexican tetra
(Astyanax mexicanus)

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, a dark stripe on the caudal fin base, and a very blunt snout.

 

Amistad gambusia (Gambusia amistadensis)

Chad Thomas

Amistad Gambusia (Extinct)
(Gambusia amistadensis)

In 1968 the Amistad gambusia became extinct in the wild as a result of the inundation of Goodenough Springs by Lake Amistad. Up until the 1980s, populations of this fish were kept at the University of Texas at Austin and the US Fish & Wildlife Service endangered species culture facility, but both populations were eliminated due to contamination by the western mosquitofish.
It is identified by its unique orange or yellow body and midlateral stripe that is often present appearing faintly red or orange.