Interesting, I didn't know crawfish would not do well in the cold, oxygen-rich waters that brookies like. I am well aware that Brook Trout require colder and clearer water than rainbows, or especially browns, but Watauga County North Carolina, especially with a spring-fed pond, can supply that quality of water year-round.
I know minnow forage species are not a good idea for trout, but I did not know whether the same would be true for crawfish. They certainly might help the flavor, as generally the more piscivorous a trout is, the worse its taste will end up (of course, that is within the spectrum of trout, which runs from "amazingly-delicious" to "best thing I've ever eaten"), but crawfish, as a crustacean, would add carnitine and the vitamins that make trout grow its pink, especially-tasty flesh.
