A European freshwater game fish (Salmo trutta) that is dark olive to purple-black above and yellow-brown with reddish spots on the sides. It is naturalized in North America. Prized and wary European game fish (Salmo trutta, family Salmonidae) that is favoured for food. The species includes several varieties (e.g., the Loch Leven trout of Britain). The brown trout is recognized by the light-ringed black spots on its brown body. It has been transplanted to many areas of the world because it can thrive in warmer waters than most other trout. It grows to about 8 lbs (3.6 kg). Oceangoing individuals, called sea trout, are larger than freshwater forms and provide good sport, as do those that enter large lakes