Gila Topminnow

Gila topminnow Poeciliopsis occidentalis

Range:

Historical: Gila River system in Arizona, New Mexico and Mexico and the Yaqui River System in southeastern Arizona and northern Mexico.

Current: Extirpated in New Mexico and rare in Arizona. There are currently 14 known naturally occurring localities in Arizona for this species.

Habitat:

Prefer shallow, warm and fairly quiet waters with dense algae and plant material but can tolerate a wide range of temperatures and current regimes

Size: Adults are typically about 2–5 cm (0.75–2 in) long

Young: This species gives live birth; young topminnows are called fry.

Diet (wild):

Decaying organic material, vegetation and insects. The species is important for mosquito control.

Life spans (wild):

Usually less than one year but occasionally longer

Conservation status:

Listed as endangered under the US Endangered Species Act

Threats:

Habitat loss from water diversion and groundwater pumping; invasive species, especially non-native predatory fish that prey upon them or compete with them, as well as bullfrogs and crayfish; water pollution

Appearance:

They are a small, silvery guppy-like fish. The breeding males are black with yellow fins.

Behavior notes:

Males will defend territories to court females.

Predators:

Birds, larger fish

Did you know?

Topminnow can survive considerable temperature extremes. They have been reported in water from near freezing to 36.7ºC (98ºF) and can even tolerate water at 43.3ºC (110ºF) for brief periods. They can also survive in a wide range of water chemistries, tolerating water as salty as seawater. They can also survive an almost total loss of water by burrowing into the mud for as long as two days.

At the Phoenix Zoo:

The Zoo maintains a breeding population of Gila topminnow. In an effort to increase wild populations of this species, we provide Gila topminnow to the Arizona Game and Fish Department to release at wild and refugium sites.