Extracted from the California Dept of FIsh and Wildlife:
The golden trout is the State Freshwater Fish of California and has long been recognized for its unparalleled beauty. Its coloration is spectacularly bright: the belly, opercula, lower jaws, and lateral line are a vivid red to red-orange. The back is a deep olive-green, fading to bright gold on the sides of the fish. About ten parr marks are centered on the lateral line and are usually present through adulthood. Body spots (usually not present below the lateral line) are large, round, dark, and concentrated near the caudal peduncle and on the dorsal and caudal fins. Paired fins are orange, and some have white or yellow tips preceded by a black band. The dorsal fin also has a white to orange tip.
California golden trout have been widely distributed outside their native range, mostly in high elevation lakes and streams in the Sierra Nevada. They were also transplanted to numerous lakes in the Wind River Range in Wyoming.
Golden Trout in Colorado
In the fall of 2013, CPW stocked 10,000 golden trout fingerlings averaging 1.7” in length in Old Dillon Reservoir. In October of 2014, a gillnet survey revealed a high density of golden trout that had grown to an average length of 5 inches. The density of fish and growth rate observed are indications that these fish will be successful in Old Dillon Reservoir. Old Dillon Reservoir is an off-channel impoundment which was drained and rebuilt by the entities who own the storage rights for water there. Because of its unique off-channel configuration, no fish can naturally migrate into the reservoir.
One limitation that has always existed in Colorado with regard to golden trout is that CPW has never had an in-state source of eggs for this species. Eggs for this species have always been obtained from out of state. Given the ease of access to Old Dillon Reservoir, this lake offers an opportunity to develop a golden trout broodstock, thus providing CPW with an internal source of eggs and the ability to provide enhanced and unique recreational opportunities to the angling public. In order to proceed with development of this broodstock, a conservative harvest regulation has been put in place. This will allow the fish to reach sexual maturity prior to being available for recreational harvest.