Rainbow trout

Identification and biology

Oncorhynchus mykiss has a bluish-green back, silver sides and black spots over the body and the tail, dorsal and adipose fins, usually with a reddish stripe along the side (WDFW). Steelhead are the same species, the form that migrates to sea, or to the Great Lakes, before returning to spawn. Most wild rainbows spawn in spring, March through May in Vermont, digging redds in gravel, although hatchery breeding has produced strains that spawn in fall. Vermont Fish & Wildlife gives a typical life of three to five years, and WDFW an average length of 11 to 18 inches, with fish over 20 inches in quality waters.

Temperature sets the season

Vermont Fish & Wildlife gives a preferred range of 54 to 66°F for stream rainbows and 45 to 64°F for lake fish, with 77°F as the most they can tolerate. That matches the WDFW calendar for lakes: fishing is best in spring, falls off as the water warms and fish move offshore and deeper, then picks up in fall when they come back to the shallows. In rivers, the warmest summer afternoons are the time to stop fishing.

Where they hold in rivers

Vermont describes rainbows in moderate- to high-gradient streams with swift riffles and deep, clear pools, using the deepest water at low summer flows and in winter, and the slack pocket water behind rocks and wood within riffles. Stream fish feed mostly on drifting aquatic and terrestrial insects. Michigan DNR notes young fish start on water fleas before adding caddisflies, mayflies and midges, and that larger rainbows add small fish.

Stocked fisheries

Much rainbow fishing is built on stocking. WDFW stocks millions each year for anglers and publishes weekly stocking reports, and Vermont notes that rainbows in its southeast depend on stocking because the low-alkalinity water there does not support reproduction. Michigan received its first rainbows as eggs from California in 1876. Where they were introduced in the West, USGS records hybridization with native cutthroat, golden, Gila and Apache trout.

The mistakes that cost fish

Wading in before looking: rainbows hold in pocket water and seams near the bank, and a careless approach clears them out. Ignoring the thermometer in midsummer, when stream water near the upper 70s °F is past what Vermont lists as their limit. And handling fish with dry hands: WDFW advises wetting your hands before touching a fish you will release, so its protective slime stays on.

Temperature range

Tackle setups

Playbook by water temperature

The legal season is a separate question

Month by month

Best waters for rainbow trout

301 waters we report on where this species is one of the main fish, each with a daily report.

Common questions