A red starfish is floating gracefully within a vibrant, blue underwater scene, surrounded by dark rocks and green seaweed.

With coral reefs and sinkholes, shipwrecks and submerged hotels, the sea is brimming with scenery that even landlubbers will ...

Like humans, fish need oxygen to survive, so how do fish breathe underwater? Oxygen helps release the energy that powers our bodies from the sugary chemical glucose in a process called respiration.