I'm going with coho. Too many spots and looking toothy. The white gum line is sticking out to me also .

Just to be safe, I'm sticking it in a bag and hiding it under the floor.......

My text book was of little use. Without the fish in hand and ability to see tail and count fin rays and gill arches, couldn't key it properly.

Always "enjoyed" walking into class at FRI on Montlake, smelling THAT SMELL and going into class and finding dozens of plates with "specimens" to key...........

I initially thought sockeye as well but the spots and eye size say coho. Maybe a hybrid? Where was it caught?

I should have said that it isn’t a river in Colorado that I recognize. Wasn’t trying to say it was the Colorado River.

Yes, there are some dandy Kokanee in Colorado. I think Eleven Mile reservoir is the location of the state record and I think it is over 6 lbs, but I have been gone for 20 years. Blue Mesa has Kokanee, as does Granby and Green Mountain. CDOW/CPW used to give away limits of Kokanee from their spawning operations.

I've seen big Kokanee develop small spots when entering into spawning phase.

My guess: Kokanee / Sockeye.

I agree with the sockeye guess, looks like a Quinault fish I hooked a few years ago. Although that was in summer.

Gotcha. Big koks are still there. The best in the world however is Flaming Gorge. Like consistent 4 - 6 pound koks. I think Herzog did a special on it a few years back if I remember correctly. I've never fished it for Koks, just monster browns and rainbows.

Those Kokanee grow some big lake trout in those reservoirs.

Yes sir. We used to ice fish for big Lakers all the time - a couple 25 - 30 pounders have been brought to hand. I even have special ice rods to handle those bigger fish. Tip a 1/2 or 3/4 oz. Pearl Glow Tube Grub with a chunk of Sucker meat and drop down. Easy pickins'.

Back to the fish in question....it's gotta be a Cockeye or something like that IMO.

Sharp teeth Coho

Soft teeth Sockeye

That being said looks like a typical green headed sockeye.

BD