Oceans cover three-quarters of the planet's surface and fish are found in just about all habitats in the sea. Bony fish come in a variety of different shapes and sizes. Some, like the goby, are tiny, growing to just one centimetre in length, while game fish such as the marlin may grow to more than three metres.

Open ocean fish can be associated with either the depths of the oceans (the abyssal zone down to 6 000m deep), or the surface water. Fish common in the coastal zone closer to land may live on coral reefs, offshore rocky reefs or on sandy bottoms and inshore sandy or rocky shores or estuaries. Estuaries and intertidal rock pools make ideal nurseries for the juveniles of many fish species.

Some fish are adapted to live near the sea bottom (demersal), while others remain higher up in the water column (pelagic) or right near the water's surface (epipelagic).

Click here for a description of different bony fish species.

Sardines, also known as pilchards, are bony fish favoured by many predators.