How Does Differences of Fish and Whale Work?

Fish and whales both live in water, but they swim differently because they're built like different things.

Imagine you're playing with two toys in a bath tub: one is a toy boat that floats on the top of the water, and the other is a toy submarine that goes all the way down to the bottom. Fish are more like the toy boat, they swim near the surface and use their fins to move through the water.

Whales are more like the toy submarine, they swim deep underwater and use their tails to move up and down in big, strong pushes.

Fish have gills, which work like a tiny sieve that pulls oxygen from the water. Whales have lungs, just like you do, so they need to come up for air, like when you blow bubbles in your bath and then pop back up to take another breath.

So even though both fish and whales are amazing swimmers, they're not the same, they're more like cousins who live in the same ocean but play different games.