Roundtail chub (Gila robusta) members of the minnow family, are native to the Colorado River drainage in waters below 7,500 feet in elevation. Roundtails can be found in cool to warm water throughout its range. Frequently, utilizing slow moving waters, deep pools, and adjoining eddies of mid-sized to larger waters, often associates with cover, such as boulders, undercut banks, vegetation, and overhanging cliffs.
An elongated fish, roundtail chub, typically are uniformly silver in color on the sides, lighter below, darker above. Their sides are flattened, the back is humped, and the tail base is very narrow compared to the body. The tail is deeply forked. The forehead is concave and the mouth is quite large and thinly lipped. While this chub has been recorded in excess of 20 inches, they typically don’t get much over 12 inches. Their life expectancy can exceed seven years.
Upon reaching sexual maturity at two to three years of age, chub spawn when water temperatures reach approximately 64 degrees in late spring to early summer. Both sexes develop an orange-red coloration lower body and fins. The females are escorted by several male. Each female is escorted by 3-5 males. The sticky eggs are broadcast over a gravel or cobblestone bottom. Females produce approximately 20,000 eggs per pound of body weight. Eggs hatch in 4-15 days and the fry begin feeding within ten days. Young chub move to margins of streams to feed, where they grow to three inches or so in the first year.
As omnivores, roundtails feed on a variety of items, with aquatic insects making up the bulk of their diets. Fish, snails, crustaceans, algae, other invertebrates and vertebrates, and detritus also are eaten. This diet is similar to trout, consequently, roundtails are readily caught by angler fishing similar tactics.
In Colorado the take and use of roundtail chub is expressly prohibited.