Photograph by Joe Platko, My Shot
A small crab hovers unharmed among the venomous tentacles of a colorful sea anemone. Though anemones are toxic, they are known to enjoy several symbiotic relationships. Some species provide safe pasture for green algae to grow and in turn receive oxygen and sugar from photosynthesis. Clownfish also dwell among the tentacles, where those messy eaters provide their anemone hosts with plentiful table scraps.