Mammals:
* Marine Mammals: Whales (including orcas, dolphins, and baleen whales), seals, sea lions, polar bears
* Freshwater Mammals: Otters, beavers, some species of dolphins
Birds:
* Seabirds: Pelicans, cormorants, gulls, albatrosses, penguins, puffins
* Freshwater birds: Herons, kingfishers, ducks, ospreys
Reptiles:
* Marine Reptiles: Sea turtles, sea snakes
* Freshwater Reptiles: Alligators, crocodiles, some species of snakes
Fish:
* Predatory Fish: Sharks, barracuda, tuna, pike, salmon, bass
Invertebrates:
* Crustaceans: Crabs, lobsters, crayfish
* Cephalopods: Squid, octopus
This is just a small list! There are many other animals that eat fish, from small insects to large sharks.