Many states stock rainbow trout into their rivers and streams for sport fishing. Although this species did not naturally occur in these areas, the state stocks its streams to lure recreationalists to fish their waters. The state also has the more novice anglers pressuring it to keep stocking the streams and rivers because they are not able to catch enough fish. Farmed trout don't only act different they also taste and look different. The wild trout have a pinkish meat with a more salmon like flavor, where as the farmed fish are whiteish and lack the salmon flavor.
Rainbow trout lose their bright coloration and turn darker in farms.
Their fins are often badly worn from scraping the concrete runway walls. The picture below shows a wild rainbow trout on top and a hatchery rainbow on the bottom. Even thought the cultured rainbow does have its down side, the upside is that it allows the recreationalist to enjoy the fun of catching rainbow trout where there would normally be none. Fish hatcheries and farms are a science of their own. There are many factors that go in to making a successful fish farm or hatchery.