Mark Rosenstein has been studying reef fish as a hobby for twenty five years, first in aquariums, then scuba diving in their native habitats. He started photographing fish for FINS, one of the first websites about aquariums, in 1994. A bit obsessive about his hobbies, this has progressed to multiple dive trips a year to amass a photo library of over 100,000 images. As the margins of his field guide collect became crowded with notes, he started reading the primary scientific literature for better insights.
He lives in Cambridge, Massachusetts with his husband, three ferrets, and a couple of Anemonefish. When not on a dive boat, he satisfies his obsession by studying birds, butterflies and dragonflies.