The Ennis National Fish Hatchery, constructed in 1931, is probably the only place in America where you can observe two genetic mutants of ordinary rainbow trout: albino and blue. (These fish are not released into the wild trout population.) Some of the trout in the hatchery ponds weigh more than 20 pounds and are more than 5 years old. The hatchery cultivates seven different strains of rainbow trout. You can learn about the operation in the small exhibit area and tour the facility. When some of those huge adults are past their use as brood stock, they too are released into lakes and streams to test fishermen.