Why would they not be able to see pink? I have never heard that. While I have not seen studies about salmonids, there are well documented studies on largemouth bass that show that they have much finer color resolution than humans.

Pink is just white with a tinge of blood to it. That would be evolutionarily useful for fish to be able to discern. So I'm betting they can see it just fine. They see my pink jigs pretty well, at least.
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