DUBAI // The colourful nudibranch and the camouflaged commensal shrimp riding on its back are among the many underwater spectacles most people will never be fortunate enough to see with their own eyes.
Living at a depth of 18 metres, the creatures can only be seen by trained scuba divers.
But an underwater photography competition organised by the Emirates Diving Association in Dubai is allowing everyone to enjoy such sights.
Warren Baverstock of Dubai took the photo of the nudibranch and its shrimp passenger in Indonesia with a professional camera.
The shot was the winner of the competition's macro category, which involves close-up images.
The British aquarium manager also won the other two professional categories, for images of fish and for photos taken with a wide-angle lens. The April 30 awards ceremony also recognised images taken with regular cameras and video work.
Nudibranches are shell-less molluscs that live on the ocean floor.
Mr Baverstock's image also shows some interesting behaviour - of the shrimp using the nudibranch for protection.
"The commensal shrimp gets a free ride and gets camouflaged," he said.
Because of their vibrant colours, nudibranchs are have very few predators.
While the image evokes a feeling of calm, capturing it was anything but effortless.
"This shot was taken in very strong current," Mr Baverstock said. "It was very difficult to compose."
To produce a good picture, divers need to be able to remain relatively motionless in the water, neither sinking nor rising.
The skill, known as buoyancy control, can only be perfected with years of practice.
It is also important to remain perfectly still, which is challenging in a strong current.
Mr Baverstock, 43, has been scuba diving for 18 years. He took up underwater photography 17 years ago, buying equipment with money from an inheritance.
"To be able to produce something that will be remembered and admired is for me very rewarding," said Mr Baverstock, who will next year be a judge in the competition.
Jeffrey Catanjal, a scuba-diving instructor who submitted pictures shot with an ordinary underwater camera, shares the love of underwater photography.
In November last year, Mr Catanjal spent two days diving in his native Philippines, at a site where a rare Pygmy seahorse was known to live.
At just two centimetres long and perfectly blended with corals, the creatures are difficult to see.
But after four dives to a depth of 25 metres, Mr Catanjal was able to produce a dramatic image.
It did not win, but he said he was happy just to participate.
"My primary concern is to share my pictures with the public and, at the exhibition, I saw some people take a picture of my sea horse," he said, smiling.