Many species of fish are consumed as food.
Fish has been an important source of protein and other nutrients for humans from time immemorial.
In culinary and fishery contexts, fish may include shellfish, such as mollusks, crustaceans, and echinoderms.
English does not distinguish between fish as an animal and the food prepared from it, as it does with pig vs. pork or cow vs. beef.
Some other languages do, as in the Spanish peces versus pescado. (source)
Can guinea pigs eat fish?
No they can’t eat fish at all and any kind of seafood. It is just not good for them and should be avoided.
For more foods that guinea pigs can and can’t eat, check out our guinea pig food list