Fish are animals that live in water. They are vertebrates, animals with backbones, and come in all kinds of shapes, sizes and colors. Fish first appeared in the oceans of the Earth about 500 million years ago, long before dinosaurs roamed our planet. Today there are tens of thousands of different kinds of fish and new species are discovered every year. Over millions of years fish have changed their features and adapted to their surroundings in order to survive.
The whale shark is the largest fish on Earth. It can grow up to 12 meters in length and can weigh up to 15 tons. In contrast tiny gobies are often only a few mm long.
Fish are important to people. They were among the first animals hunted by primitive human beings. Millions of people all over the world depend on fish as a main form of nutrition. In many coastal countries, for example Japan or Norway, people depend on fishing to make a living.
Fish are a part of the food chain. They eat animals and are eaten by other sea creatures, thus keeping up the balance of nature.