Horned Sea Star, Protoreaster nodosus

The horned sea star (Protoreaster nodosus), also known as the chocolate chip sea star, is a species of starfish that is classified within the Oreasteridae family. It can be found in the Indo-Pacific region and prefers a habitat within hidden sandy or muddy areas, with substrate such as coral, but can be seen in sea grasses. This species can reach an average diameter of 11.8 inches with four to six arms, although it is more common to see star-shaped individuals with five arms.

It is typically red or brown in color, but can be tan like the color of cookie dough.

The main feature of the horned sea star is its horns, which occur along its arms and around the center of its upper body. These spines are black in color and serve as a defense mechanism, although some individuals have blunt spines. Because of these spines, very few species attempt to consume this creature, and it is thought that species like brittle stars and shrimp take advantage of this protection by living on the sea star. The undersides of the arms hold purple or pale pink tube feet that can be transparent.

The horned sea star is thought to be an opportunistic predator, preferring to consume immobile creatures like sponges or corals in captivity, as well as snails. In large public aquariums, this species is known to consume a wide variety of food including clams, shrimp, and chopped squid. This species is popular among collectors, but it requires pristine water conditions, so it does not often survive in personal aquariums.

This species is also popular in the seashell trade, especially in Pacific and Asian countries. Individuals are dried and sold for decorations, but this practice is causing a decrease in some populations.

Image Caption: Protoreaster nodosus, Oreasteridae – Kambodscha/Cambodia, Insel Kaoh Ruessei SSE Sihanoukville. Credit: Franz Xaver/Wikipedia (CC BY-SA 3.0)