The deep sea is home to an array of marine creatures, and fish are by far the most well known. But their diversity means they do not comprise a single group, and they are not all closely related. In this two-part film, we take a look at the different groups of fish and how their adaptations differ.
Part 1 examines the two groups of bony fish (Osteichthyes): the ray-finned fish, and the lobe-finned fish which includes the elusive deep sea coelacanth.