Rainbow trout are silvery-gray to dark-green on the back and sides. They have a pinkish or reddish lateral stripe, sometimes with lavendar or orange overtones, from the gill cover running the length of the fish to the tail. The caudal fin has rows of small dark spots, and there are more small blackish spots sprinkled on the head and sides, and spotting on the dorsal and adipose fins. The belly is whitish. The lower fins are pale-pink without spots. At spawning time, males become deeply colored with an intensely red side stripe. Steelhead can be separated from similar-looking coho and chinook salmon by looking at the inside of the mouth. The mouth is completely white in the steelhead. In the salmons, the mouth has some gray or black. Steelhead and other deepwater, big-lake rainbows are more silvery than stream fish, with less of a side stripe. Great Lakes steelhead can grow to 30 inches and larger.
The Rainbow Trout was introduced into NH in 1878 and has been stocked extensively since that time. It thrives best in cold water but can withstand higher temperatures than the Brook Trout. It is well adapted to either lake or stream life. It eats mainly insects except in lakes where the diet of larger fish consists mainly of baitfish.
This fish may be taken in a variety of ways and is easily caught on flies. It jumps repeatedly when hooked and puts up a good fight. It has an excellent flavor when taken from wilderness streams, but only fair when not in prime condition or recently released from a hatchery. Rainbows are very popular with anglers as they are easily taken, fight well and are very tasty. The average size in NH streams is between 6-12 inches and lest than 0.75 pound. In some large lakes(Ex: Winnipesaukee) rainbows between 3-5 pounds are not unusual. The state record for NH for Rainbow Trout is 35.50" in length, 15 lbs. 7.2 oz. in weight, caught on the Pemigewasset River in Bristol, NH on 9/16/1996 by Lance King.
-Massachusetts State Record is 13 lbs 13 oz caught by Jeffrey Greco in 1999 at Wachusett Reservoir