Haven't seen any tapeworms in salmon although I have caught rainbows from certain lakes with tapeworms. Tapeworms are usually found in the intestine. The "head" of tapeworms usually have suckers and hooks to attach to the inner wall of the intestine where they absorb nutrients from the host. I have seen the occasional round worm in salmon around the rib cage area. Round worms are usually transparent and can be seen coiled in the tissue if the fish fillet is held up to a light. Halibut seem to have large numbers of round worms in the tissue around the belly/rib cage area. A lot of people discard this part of the halibut. Restaurants serving sushi are required to freeze fish for several days at a specific temperature to kill any parasites and daily records of freezer/cooler temperatures must be kept.