I am surprised by the number of people I fish with who confuse one species of trout or salmon for another. I’m not trying to judge. It is important, however, to know what you’ve just caught, especially in the context of protecting certain species and complying with fishing regulations when you keep fish to eat. Obviously, you don’t want to go over your limit. And in some places, anglers are encouraged to take one kind of fish in order to limit natural competition that threatens another. But it will defeat the purpose if you kill the wrong fish. And it could land you in trouble.

Believe it or not, I’ve seen people call rainbow trout brown trout, brook trout cutthroats, pink salmon silver salmon, and so forth. Sometimes that red band on the side of a rainbow is subtle, and people see spots, so they assume the fish is a brown trout. It’s easy to confuse a cutthroat for a rainbow or a cutt-bow hybrid if you don’t look for the little slashes of red or orange below the fish’s jaw.

When I’m fishing with someone and they say, “Hey, look it’s a rainbow,” when I know it is obviously a cutthroat, I take time to correct them, politely pointing out the telltales that help them identify fish. It’s hard to match what you see in a book or magazine with what you actually catch on a river. Time and experience catching many fish are ultimately the best teachers.

So I’m going to start digging through the archives of my photos to find some shots that will quiz you on fish identification.

I’ll warn you in advance that some of these are tricky, starting with this shot right here.

Can you tell me what species this is? For the commenter who gives the most complete answer, including a rough estimate of size, I will send a signed copy of “The Orvis Guide to Fly Fishing for Carp.” And no, the fish in this shot is definitely not a carp.