green sea anemone
A green sea anemone fluoresces using a combination of blue light and a yellow filter. An excitation filter is placed over a flash fired off camera at full power, and a yellow filter is attached to a macro lens to reveal the fluorescent algae living within the anemone.
EXIF 1/100 f/13.0 ISO200 100mm
580ex at full power fired via FlexTT5 just above the frame.