Frozen fish is the only fish I buy from supermarkets
I remember once approaching the fish section at Morrisons looking for some Skate, and smelling the ammonia from several feet away!!
I made a hasty retreat.
It's a shame as it puts people off fish. Freshly caught fish tastes nothing like the stuff that's been hanging around for several days. Fresh mackerel for example is really meaty and doesn't taste 'fishy' at all. Really delicious