I've cleaned 3 that had a worm like parasite in the meat. I cut it out, bag the fillets, cook them when I'm ready.
The worm is rolled up in a ring, when unrolled it's over an inch long, 1/16 to 3/32 dia., like a small red wiggler. Hard to the touch but I was wearing rubber gloves.
I wonder how many are ate by people that scale and gut their catch?
FLESH worms, they live in the meat.
google fishparasites, see what you find.

