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Unlike fish, dolphins must come to the surface to breathe.

Although they may look similar, a dolphin and a fish is not the same thing, as a dolphin is a mammal. Dolphins give live birth, they feed their offspring milk, they breathe air, and they have hair before they are born.

Another difference between dolphins and fish is how they swim. A dolphin moves its tail up and down to swim, but a fish moves its tail side to side.