Fuorescent image of a Montastrea cavernosa 

Fuorescent image of a Montastrea cavernosa coral colony growing on the seawall at Ft. Jefferson, Dry Tortugas National Park. The fluorescent image was taken at night using blue LED lights to stimulate fluorescence. The green color is attributable to a compound called green fluorescent protein (GFP) contained in the coral tissue, not the symbiotic algae.