The honor of being one of the most spectacular fresh-water fighters must go to the Rainbow Trout. He takes a dry fly, or wet fly, or spinning lure without showing as much discrimination as do the Brook Trout and Brown Trout but during the ensuing battle he's out of water as often as he's in it, each time exploding into the air like a submarine missile. And at the end of these violent acrobatics you're often left with nothing but a rod with a snapped leader. The Rainbow is also distinguished for being one of the largest Trout. His world record is an amazing 37 pounds! And in addition, when his lake or river connects with the sea he frequently becomes "anadromous," taking trips to salt water and returning to fresh water to spawn. In this case he's called a Steelhead Trout.
The original waters of the Rainbow Trout were those of the West Coast from California to Southern Alaska, but he has been transplanted all over the world. One reason has been that he's an easy species to breed and rear in a hatchery. Another is that his eggs, if kept moist, will stay alive for months, even without refrigeration. And he makes himself at home in almost any lake, river or stream as long as its temperature doesn't climb above 70 degrees and as long as there's enough food to satisfy his voracious appetite. In spite of his record size, his average weight is 2 pounds. The giant specimens are found in Lake Pend Oreille, Idaho, as was the 37-pounder, and for years it was thought that these were a different species of fish. But finally it was discovered that their great size was due to the lake's huge horde of small Blueback Salmon upon which they fed. In general, the larger the water, the larger the Rainbow Trout. But from the angler's viewpoint, there's an objection to the monster Rainbows: the larger they are the lazier they are—the less they fight and the less they jump. And a Rainbow's jumps are half the thrill of catching him.
The Rainbow Trout is a true Trout with a forked tail, unlike the Brook Trout which is classified as a "charr." His back and upper sides are an olive-blue fading to a bluish-silver on the belly, and except for his belly he is covered with numerous small black spots. But his most outstanding coloration, which inspired his name, is a broad pink band extending along his sides from gill covers to tail. In older male Rainbows living in the dark depths, this pink frequently deepens to a brilliant and startling crimson. As a Steelhead, the seagoing Rainbow has the same coloring but the salt water has a fading effect. His back lightens to a pale blue and his sides become silver, the black spots almost disappear and he has only a suggestion of a pink band. But he regains his former brilliance some time after his re-entry into fresh water.
The Rainbow Trout's diet depends on his size. Up to one pound he gorges himself on insects and flies, but the heavier fish look for more substantial food, chiefly other fish. He is a wanderer, even when landlocked in fresh water. In a lake he may be roaming anywhere in search of food. Here the accepted method of taking him is trolling from a boat with a stiff bait-casting rod, a line of 10-pound-test (stronger if the lake contains heavy fish), and a large silver spoon or wobbling Bass plug. Lures must be weighted so they'll run deep. In the great depths of Pend Oreille, metal lines sometimes are used to carry the lures to the bottom, but all this extra weight limits the Trout's ability to fight.
In a stream the Rainbow likes the swiftest water, particularly the boil at the bottom of a falls, the riffles and the fast water that rushes beneath an overhanging bank. But if you miss a good fish at one of these spots, you won't find him there tomorrow because he's a wanderer even in a stream. Usually it's spring or summer when you meet him, and then he's traveling downstream after his winter spawning in the stream's headwaters. In late fall he starts back up again. Why the downstream migration ? Maybe he's instinctively seeking the sea, as some biologists think all Rainbows do, not only the Steelhead. In large streams and rivers, spinning lures are deadly for Rainbow Trout, more so than for Brook or Brown Trout because of the Rainbow's extra fondness for minnow-like lures, but fly tackle always provides the most sport even when it doesn't take the most fish. Use the same rod, line, leader and flies recommended for Brook Trout, and also the same methods. Of course, when heavier fish are around, a heavier leader is advisable. And there's an addition. Since the Rainbow Trout prefers minnows, he's especially susceptible to flies that resemble these bait-fish—the streamer flies. Choose a streamer pattern such as a Grey Ghost or Green Ghost or a Nine-Three, and cast it up and across the stream, letting the current carry it down and below you. But as it drifts, retrieve it in short, snappy jerks so it resembles a darting minnow. If there's a Rainbow within range and he's at all hungry, it will be hard for him to pass it up.
Sometimes a big stubborn Rainbow is as much of a bully as a big Bass—and just as easy to anger. There's a way to rile him up and make him biting mad. Always carry a couple of huge, gaudy Bass-type flies in your tackle, and when a Rainbow ignores your perfect imitation Trout fly you offer him so skillfully, insult him! Tie on one of the monstrosities, toss it across the stream and drag it in so fast it skitters over the surface, leaving a wake behind it. What he thinks it is is a mystery, but 9 times out of 10 he'll smash it!