Underwater fluorescence is produced by a protein and is most easily observed under ultra-violet light so we grabbed the UV torches and walked into the house reef as soon as it got dark.
Straight away we were transfixed by the sight of a fluorescent green tube anemone (Cerianthus) with a brilliant green centre and delicate green dots studding the anemone’s arms.
Less than a metre away was a swimming fluorescent flatworm and a goby which had two glowing fluorescent green spots on its tail, perhaps to fool predators into thinking these are the eyes and thus misjudging a deadly attack.
Many corals on the house reef display the mesmerizing glowing green light such as Lobophyllia sp (looks a bit like brain coral), Fungia (mushroom coral), and several species of Acropora (staghorn). My personal favourite was the Turbinaria sp – a hard coral forming large glowing vase-like structures, really creating a sensation of diving on a bizarre glowing alien planet.
The best part was we didn’t even have to go deeper than 12 metres/ 40 feet and with the house reef’s easy access we were in and out again without being late for dinner.
Carlos Villoch, who has captured brilliant images of fluorescence, said that our house reef was one of the best sites he’s seen for this type of dive, so that’s yet another reason to come visit us here at Critters at Lembeh.
We have UV torches for rent so you can check out this amazing phenomenon for yourself. Give it a try and experience a night dive like you’ve never seen before!