Steelhead is good to eat if you cook it right. The way I have done it in the past that worked well is not to fillet it, but to cut it into steaks after you cut the guts out of it. Clean the guts out, then cut it into 1-2" steaks from the spine down to the stomach. Wrap each steak in tin foil with butter, seasoning, and some lemon and throw it on the grill.