Yes.
well in the wild they feed on bloodworms and things
Yes, of course. They might even like it.
They are just carp and they feed like every other wild fish
Penguins are wild animals, but they can care for themselves they have a natural instinct that they know when and how to hunt for food as in Fish and Krill
Yes, hawks do fish for their food in the wild.
What to feed a fish is not dependant on whether it was wild caught or captive raised, you feed a fish based on whether it is a predator, omnivore or herbivore. Though wild fish will more often need fresh foods, instead of prepared. At least when first aquired.
yes you can.
no, wild fish must get sick if they eat fish food
They eat any type of fish that they can catch!
food
Fresh water crayfish in the wild feed on both living and dead plants and animals. Those kept in aquariums can eat fish food and plants, but will also feed on small fish which they can catch.
In captivity the owner has to feed the fish. In the wild the fish hide and hunt. They eat small water born crustacea like daphnia and insect larvae such as mosquito larvae..