What happens to the ocean if we take out all the fish?

Find out about the vital role fish play in sea life.

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The ocean is massive and covers most of the surface of our planet. In addition to its size, it’s packed with life – an astounding range of plants, microbes, worms, corals and crabs, all the way to large squid, whales and, of course, fish.

The ocean is full of fish, so many that they make up the second-largest amount of all carbon (the material that makes up living things) in the entire animal kingdom – just behind the group containing insects and crustaceans. Most people only get close to the ocean from a beach or in a boat, so it can be hard to wrap your head around how many fish there really are. However, the ocean is swarming with them, from its surface to its depths.

These fish come in all kinds of shapes and sizes, ranging from tiny sardines, guppies and blennies that you might see on a coral reef, to massive tuna and whale sharks that swim out in the open ocean. They perform all kinds of roles in their ecosystems (communities of living things) that support the lives of other living things around them. If they disappeared one day, the ocean would look very different.