During mass coral bleaching, when many corals turn white, some corals may have flourescent bright colours. I have wondered why.
Some excerpts from the article "This Eerie Neon Glow Coming From Bleached Coral Could Actually Be Good News" Jorg Wiedenmann AND Cecilia D'Angelo on Science Alert 22 May 2020. With photos of some colourful bleaching I've observed on our shores.
"Ocean heatwaves cause vast coral bleaching events almost every year due to climate change, threatening reefs around the world. The high water temperatures stress reef building corals, causing them to eject the photosynthetic algae that reside in their tissue."