This video says about itself:
From New Scientist about this:
24 June 2015
Glowing world of rainbow corals found in the Red Sea
There’s a fluorescent disco world in the Red Sea. An assortment of glowing corals has been discovered more than 50 metres down, outshining the monotone green varieties seen in shallower waters.
Jörg Wiedenmann of the University of Southampton in the UK and his team were surprised to see specimens with a red or yellow glow at depths of over 50 metres. “This could only be due to the presence of fluorescent pigments,” says Gal Eyal of the Interuniversity Institute for Marine Sciences in Israel, a member of the team.
The lobed brain coral … changes colour from green to deep red when illuminated with ultraviolet light. Optical properties like this could be useful for biomedical imaging, for example to help highlight cell structures under a microscope, track cancer cells or screen new drugs.
Wiedenmann and his team want to find out why the corals produce the pigments. In shallow water, colours act as a sunscreen. But deeper down, where sunlight doesn’t penetrate, that can’t be the case. Yet the pigments must have a role since it takes a lot of energy to produce them.
The pigments might help the corals harvest energy from what little light is around, then feed it to symbiotic algae that provide them with energy-rich sugars. “The underlying mechanism is not understood,” says Wiedenmann. “Hopefully our future work can reveal their function.”
Corals also seem to be capable of other tricks. Although reefs are threatened by climate change, they are also able to put up a fight, sometimes evolving rapidly to adapt to their changing environment.
Journal reference: PLoS One, DOI: 10.1371/journal.pone.0128697