About This Site

Mark Rosenstein has been studying reef fish as a hobby for twenty five years, first in aquariums, then scuba diving in their native habitat. He started photographing fish initially for one of the first websites about aquariums, FINS, starting 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.

Looking for help identifying a fish? Please post it to iNaturalist.

He lives in Cambridge, Massachusetts with his husband, three ferrets, and a couple anemonefish. When not on a dive boat, he satisfies this obsession by studying birds, butterflies and dragonflies.