MY BEST SEA ANIMALS Leave a Comment / General / By Teacher SEA LIONSea lions haul out in large colonies on rocks and sandy shores on the Islands. They move into the water to feed and cool off as needed. DOLPHINDolphins may swim through the water as gracefully as any fish, but they are not fish. Dolphins are mammals. JELLY FISHJellyfish are mainly free-swimming marine animals with umbrella-shaped bells and trailing tentacles. SEA CRABSea crabs are a type of crustacean, meaning they have no backbone and are covered with a hard shell. Sea crabs live in the seas and oceans around the world. FISHFish are aquatic, craniate, gill-bearing animals that lack limbs with digits.