Two of the more popular species of trout in the world are the brook and rainbow trout. The two fish are really quite different, especially when it comes to both color and size. The one thing that they both most certainly have in common is the fact that they are both trout, and popular trout at that.
Rainbow Trout – These beautiful fish have been stocked in most streams by state hatcheries, and have become the backbone of our trout fishery in the United States. Rainbows have glowing rows of black spots on the back, sides and tail. A pinkish-red band can be found on both sides of the fish, thus the name "rainbow". This fish is noted for its spectacular leaps and hard fighting when hooked. Rainbow trout thrive in clear, cool streams and rivers but have been known to survive in warm silt bottom streams as well. Rainbows are larger than Brook trout and generally dominate areas shared by the two species. Given the proper conditions a rainbow trout can grow to be over 25 pounds, although this is the exception, rather than the rule. In normal situations an average rainbow trout is 17-20 inches or about ½ to 3 pounds.
Brook Trout – Brook trout are distinguished from Rainbow trout by a lack of any black spots on their body. Brook trout have a dark green, worm-like marbling on their back and dorsal fin and bluish halos around some of the reddish spots on their sides. They are arguably the most beautiful of the four major trout species. Brook Trout have been termed the white rat of aquatic science because more experimental work has been done on this species than any other. Brook Trout live naturally under cool water conditions that are clear and pure. This means that they like clean, clear mountain streams. Brook Trout are much smaller on average than Rainbow Trout, and in most parts of North America a twelve inch brook trout would be considered a real trophy. Although is parts of Labrador, Brook Trout can grow to be over 10 pounds!
With these description, you should have a better understanding as to the difference between rainbow trout and brook trout. Fishing for them is similar in many respects, although with the normal size difference; small "brookies" may require quite small tackle in order to catch effectively. Both species feed on similar prey such as aquatic insects, small fish, flying insects, and of course good old American worms. Both of these species are very appealing to the eyes, and a brook trout in the Fall (when they spawn) is as beautiful as any fish that you have ever seen.