A friend of ours recently cooked up some fish she had bought in a wholefoods market. After eating most of it, she discovered little white worms in the meat (about 1 1/2" inches).
She brought the fish back to complain, and the fish monger told her that many kinds of ocean fish (cod, swordfish and maybe some others) have these kind of worms. He told her they were always there but most people don’t notice them and they’re not visible until the fish is cooked thoroughly.
Sorry for the sketchy description (this is a third hand story) – but can this be true?