Alex Tattersall's Image

At the end of a shore dive at Marsa Nakari, Egypt, Alex encountered a huge shoal of baitfish.

Sensing a photographic opportunity, he rushed out of the sea, got a fresh tank of air and re-entered the water 'The shimmering ball of fish,' says Alex, 'swallowed up my next three hours.' Local predators soon arrived, including a common lionfish, which lunged at the baitball, picking off individuals. Alex concentrated on highlighting the contrast between the striking, venomous lionfish and the silvery shoal. 'This photograph,' says Alex, 'represents a turning point in my life because that trip motivated me into setting up my own underwater-photography company.'