Colorado's state fish — thought extinct in the 1930s, rediscovered in 2012 in a tiny remnant population. One of the great recovery stories.

Also called: Greenback

Native status: Native; federally threatened; endemic to South Platte/Arkansas River drainages

§ Quick facts

SizeLength 15–30 cm (6–12 in) in native habitat
Weight150–700 g (5 oz–1.5 lb)
LifespanWild 5–7 years
OrderSalmoniformes
FamilySalmonidae

§ Encyclopedia

The greenback cutthroat trout is the easternmost subspecies of cutthroat trout. The greenback cutthroat, once widespread in the Arkansas and South Platte River drainages of Eastern Colorado and Southeast Wyoming, today occupies less than 1% of its historical range. It is currently listed as threatened under the Endangered Species Act. It was adopted as the state fish of Colorado on March 15, 1994, replacing the unofficial rainbow trout.

Source: Wikipedia — Greenback cutthroat trout Licensed under CC BY-SA 4.0

§ Identification

Field marks. Bright crimson throat slash; large dark spots on tail and back; greenish-bronze body. Largest spots of any cutthroat subspecies.

Similar species. Other cutthroat subspecies — distinguishable mainly by spot pattern, range, and DNA. Rainbow Trout (no throat slash; hybridizes with greenback).

Voice. Silent.

§ Diet & behavior

Diet. Aquatic insects (mayflies, caddisflies, midges), terrestrial insects falling onto water, occasional small fish.

Behavior. State fish of Colorado. Believed extinct by mid-1900s; rediscovered in tiny remnant populations. Genetic analysis in 2012 revealed only a single 4-mile stretch of Bear Creek held genetically pure greenback cutthroat — other "greenback" populations turned out to be Colorado River cutthroat. Recovery effort focused on Bear Creek lineage.

§ Range

South Platte River drainage, Colorado

§ Habitat

Cold mountain streams

§ Threats

Hybridization, drought, wildfire impacts, climate-driven stream warming.

§ Conservation status

According to the IUCN Red List, the greenback cutthroat trout is currently classified as Endangered.

§ What helps

Support greenback recovery. Don't release rainbows. Donate to Colorado Parks and Wildlife.

Support our work More ways to help

§ Further reading

§ Sources cited

  • Colorado Parks and Wildlife
  • USFWS Mountain-Prairie Region
  • Trout Unlimited
  • IUCN Red List 2008