Question

Explain how fish which live deep in the ocean nearer to the sea bed move for their prey,even when it's body is not streamlined

Answer 1

Some of the fish even have lunglike swim bladders to control their buoyancy: They move up in the water column by secreting gas into the bladder and inflating it, and down by reabsorbing gas into their blood. A swim bladder doesn't collapse at depth because the gas inside is at the same pressure as the water outside—which means if that external pressure suddenly decreases, the bladder will swell catastrophically.