Jellyfish can be many sizes. They can be as large as a human or as small as a pinhead.

Seahorses like to swim in pairs by linking their tails together.

Clownfish are also called anemonefish because they live with sea anemones.

There are over 4,500 kinds of crabs. Crabs live in all of the world's oceans, in fresh water, and even on land. Many crabs walk sideways.

Sea turtles have been around for about 150 million years. Green sea turtles can hold their breath underwater for up to five hours.