The Colorado river is hot. We made it over the divide and onto the river by 8:00. Got into a beautiful spot lined with cottonwoods on one side and a steep mountain slope on the other. We saw a minx working the opposite shore and thought if it is good enough for her it will work for us. There was nothing hatching that early so I began with a prince nymph and a BHPT. I landed about a dozen fish before lunch on all sorts of flies including a BH buckskin, flashback RS-2 and PMD emergers. My buddy found some risers and did well with a PMD cripple but I could only manage a couple up top on a small elk hair caddis. We roamed after lunch checking out rumored secret spots without much success. In the evening we happened upon a Secret BLM section and things got stupid. I took a few on the buckskin. The fish liked it best on the swing instead of dead drifted. Softhackles shoud have worked since it was caddis water but they met with only marginal success. I tied on a serendipity that had been sitting unused for quite a while. I tied these years ago and never really had much luck with them. First cast unweighted just under the surface and wham. Fish on. For the next 3 hours we hammered the fish on Size 16 serendipitys on the swing. The fish are not huge, the largest measured right at 16", but they fight like champs. My buddy was not prepared for the viscious strikes and lost at least 5 rigs until he switched to 6 pound fluorocarbon. A good start turned into another epic day in Colorado.