In Rock Creek Canyon, four species of trout exist, including brook, brown, rainbow, and golden. Rainbow trout can be found in most creeks and lakes in the canyon, along with brookies and browns, whereas, goldens are quite elusive. Only the highest lakes hold goldens. In years past, one lake also held cutthroat trout, but the lake suffered a winter kill during the 2000-2001 winter. It's unknown if fish have been reintroduced to that lake.
Rainbow trout are routinely caught out of both Rock Creek Lake and Rock Creek, and an angler may get lucky and catch a huge brown. The record trout caught out of Rock Creek Lake is a 15 pound, 8 ounce female brown caught in 1985. It is on display at Rock Creek Lakes Resort, along with several other large trout. Photos of the year’s largest catches can be viewed on the fish board located just inside the door of the resort. Nearly all fish on that board weigh over 3 pounds, displaying the area’s abundance of nice-sized trout.
Large Alpers trout, named after the man that raises them, Tim Alpers, are put into Rock Creek Lake and Rock Creek at various times during the season, giving people a better than average chance of catching a large trout. Alpers trout average around 4 pounds, but can be larger than 12! The largest one ever caught out of Rock Creek Lake was over 11 pounds! In addition to these Alpers trout, the Department of Fish and Game also stocks trophy brood stock rainbows during the fishing season at times.