Fish are crucial for the natural growth of the thriving ecosystem and serve as the primary food source for other fishes, birds, mammals and reptiles. They also help maintain the insect and plant population and are a secondary food source for larger animals as well as humans.

The Grand Teton National Park is home to more than a dozen different species of fish, including the native Mountain Whitefish, Speckled Dace, Longnose Dace, Mountain Sucker, Utah Sucker, Red side Shiner, Snake River Cutthroat Trout, Mottled Sculpin and Paiute Sculpin as well as the non native Utah Chub, Blue Head Sucker, Lake Trout, Rainbow Trout, Brown Trout, Eastern Brook Trout and Arctic Grayling. With a wide variety of trout, the park is renowned the world over for trout fishing and dozens of tourists as well as nature lovers flock the grounds during the trout season to enjoy the abundance of natural beauty and fresh produce of the region.

Fish species found in the Grand Teton national Park vary on the basis of their shape, size as well as behavior, diversity and habitat. While the Utah Chub prefers warm and shallow slow moving water, the mountain whitefish is usually found in colder, deeper and fast moving streams and rivers in the area. On the other hand, the cut throat trout preys on smaller fish and insects while the mountain sucker lives on algae.