Hard corals are the reef-building champions of the tropics. They thrive in low-nutrient, oligotrophic waters and create habitat for countless species of fish and invertebrates. Hard corals have a symbiotic relationship with photosynthetic algae that live in their tissues and convert sunlight into food for the coral. Many coral species are imperiled by warming ocean waters due to climate change and may expel these algal symbionts during a proceess known as coral bleaching. This diagram shows the diversity of forms that hard corals exhibit. Clockwise from upper right: large branching, plate-like, foliaceous, encrusting, free-living, fine branching, massive, and columnar.

Illustration created for publication in The Ocean’s Menagerie (2025) by Drew Harvell.

11x17” and 6×9” prints ship flat in a sturdy photo mailer.