Fish

Fish are vertebrates (animals with backbones) that live in water all of the time. They have hairless, streamlined bodies with fins and a tail. Many have a protective layer of...

How do fish breathe?

Most kinds of fish cannot survive out of water, because they do not have lungs to breathe air. Instead, they are able to filter oxygen from the water around them using slits in...

Coral reef fish

Coral reefs are found in the warm, clear, shallow waters around volcanic islands or rocky coastlines of tropical seas. The reefs teem with wildlife, including many species of...

Deep-ocean fish

Fish that live in deep waters all the time are adapted to the extreme cold, permanent absence of light, high pressure and scarcity of food. They have large, extremely sensitive...

Eels

Eels are snake-like fish that lack scales. There are around 800 species, ranging from some kinds just a few centimetres in length to the 3-metre (10-foot) giant moray. They have...

Great white shark

The great white shark is a fierce predator, with a grey back and white belly. It may grow up to 6 metres (20 feet) long. Great white sharks prefer cool coastal waters, but have...

Hammerhead shark

Hammerhead sharks are a family of sharks that are distinguished by their extraordinary hammer-shaped heads, with eyes at each end. This unusual design gives them the widest field...

Lampreys and hagfish

Lampreys and hagfish are ancient species that resemble fish in their early stages of evolution, more than 300 million years ago. Neither are considered to be true vertebrates...

Piranhas

Piranhas are freshwater fish native to the streams and rivers of South America, such as the Amazon, Orinoco and Paraná rivers. There are between 30 and 60 different species of...

Rays and skates

Rays and their relatives, the skates, are cartilaginous fish with flat bodies and long, narrow tails. Flattened relatives of sharks, most live on the sea floor in coastal waters...

Salmon

Salmon is the name for the family of fish that includes species of both salmon and trout. Most salmon hatch out in fresh water, migrate to the ocean and return to the same...

Seahorses

Seahorses are small fish with horse-shaped heads and curled tails. There are 54 species of seahorse. They are found in shallow temperate and tropical seas across the world, living...

Sharks

Sharks are a kind of cartilaginous fish: they have skeletons made of soft cartilage (gristle) rather than rigid bone. They live in all the world’s oceans. Sharks are mostly...

Sharks and rays A-Z

Whale shark

The whale shark is the biggest fish in the ocean, growing up to 12 metres (39 feet) long. It lives near the surface of the warmer oceans and far from land. The shark is brown with...

Extraordinary fish

Many ocean creatures may look extraordinary to us, but the colours, shapes or other distinctive features they have are there to help them to best adapt to their ocean environment...

Fish A-Z