These are polyps of the sun coral. Contrary to its name, these polyps only come out at night. During the day, the flamboyantly coloured polyps are hidden away in non-descript grey tubes. Most divers wouldn’t even notice these corals during the day, they are so dull. Yet at night, they are one of the most vibrantly colourful elements of reef life. Unlike most other stony corals, the sun corals do not contain algae, so they don’t derive any energy from sunlight. As a consequence they are often found in caves or under over-hangs, where other stony corals won’t live, because there is not enough light. Great Barrier Reef, Australia.
Canon EOS 5D MkII; Canon EF 100mm f/2.8L Macro IS USM lens; Seacam housing; Ikelite DS125 strobes.
This image has been featured in the following groups:
Awesome Animal Kingdom; Color Me A Rainbow (In Nature); Rainbow; Topshelf Wildlife