The blue sea star (Linckia laevigata) is a species of starfish found in the shallow waters of the Indian and Pacific oceans. Known also as the blue Linckia and the comet sea star, this starfish is usually blue in color but can also be found in shades of aqua, purple, and orange. This species grows to a maximum size of 12 inches (30 centimeters). It is a nocturnal feeder, coming out only at night to scavenge for algae, microbial film, and other scraps of food. This species is popular in the aquarium industry because of its bright blue color.