Photo: Necklace sea star on coral
A necklace sea star nestles among the C-shaped emerald tentacles of anchor coral in the western Pacific Ocean.
 
Photo: Orange sea star on a sea fan
A red-and-yellow necklace sea star clings to a sea fan in the Maldives.
 
Photo: Sea star among kelp
An ochre sea star (background) shares a kelp-strewn beach with a bright-red cousin at low tide on Washington's Tongue Point.
 
Photo: Close-up of a purple sea star
A sea star with vibrant purple coloring rests on an ocean floor
 
Photo: Close-up of a sea star
The white dorsal plates of this sea star, photographed in the western Pacific Ocean, give it a calico pattern that helps it blend with its rocky surroundings.
 
Photo: Crab crawling on sea star
A small crab skitters across a brilliantly colored blue sea star in the western Pacific Ocean.
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A close-up of a Nardoa frianti sea star in Sulawesi, Indonesia, shows this species' highly contoured dorsal side.