I've poached cod fillets in milk many times. It's wonderful with mash, home-made parsley sauce and something green. Best thing on earth if you happen to have toothache. The only thing I ever do with salmon is fry it in butter or cut it into small chunks and add it at the last minute to a spicy arrabbiata sauce, in which it's cooked in under two minutes. I'm never going to be buying pink salmon or any farmed salmon, and I always ask.