Rainbow Trout (Oncorhynchus mykiss) - Introduced

Hatchery-raised rainbow trout.

A profusely spotted, 14-inch hatchery-raised rainbow trout.

Identification. Anal rays 8-12. Adults - Small dark spots on a light background. Mouth large; jaw extends well beyond posterior margin of eye. Many spots on tail fin. No pale halos surround spots on sides. Usually has some trace of a horizontal pink band. Tail fin nearly square or only slightly concave. Color variable; brownish, greenish or grayish on back to silvery on sides. Parr - Adipose fin with dark border, spaces between parr marks usually greater than or equal to width of parr marks. Tail fin concave or only slightly forked. Red or yellow spots not present on sides.

Lightly-colored rainbow trout.

This 12-inch rainbow trout displays only a hint of a pink lateral band.

Size. Commonly 8 to 16 inches. State survey max. size 24 inches. Conn. State Record 14.6 pounds, 30 inches. Max. reported size 3.9 feet. World Record 42.1 pounds.

Distribution. Native to the United States and Canada west of the Rockies from Alaska to California, in a few high elevation areas of Mexico, and in areas of the North Pacific in Asia. Have been widely introduced throughout the world. Rainbow trout are stocked into many Connecticut lakes and larger fishable streams. Although naturally spawned “wild” rainbow trout are occasionally found, only one known self-sustaining population exists in Connecticut (Hubbard Brook, Hartland).

Wild brown trout distribution map.

All maps created in 2009. See CT DEEP Fish Community Data for updated distributions.

Habits. Rainbow trout prefer cold, well-oxygenated lakes and streams. They will move up streams into faster, well-aerated areas as temperatures rise. Can be readily caught by angling on a variety of small baits and lures.

Comments. Rainbow trout seldom survive the summer in Connecticut lakes or streams. Large fish caught by anglers are typically surplus broodstock (i.e. stocked at large size). If not harvested quickly, some strains of rainbow trout tend to emigrate from stocked streams. Naturally reproduced rainbow trout are rare in Connecticut, in part because domestic strains are not suited for spawning here.


Text and images adapted from Jacobs, R. P., O'Donnell, E. B., and Connecticut DEEP. (2009). A Pictorial Guide to Freshwater Fishes of Connecticut. Hartford, CT. Available for purchase at the DEEP Store.