Blood stars are the most brightly colored sea stars in the intertidal zone. They are usually brilliant red or reddish-orange with a texture that feels similar to fine sandpaper. They have a small disc usually surrounded by four to six long, tapering arms which can measure up to 10 inches (approximately 25 cm) in diameter. Blood stars feed on bacteria and other tiny particles which they capture in mucus and sweep into their mouths. These sea stars may also feed by applying their stomach to the surfaces of sponges and bryozoans. They spawn in late winter and early spring. Larger females discharge their eggs into the sea but smaller individuals retain the eggs in brood pouches around the mouth until they hatch. Like all stars, Blood Stars are related to sea urchins and sand dollars.
Blood stars are common from the Aleutian Islands, Alaska to Baja California. They live on the protected sides of rocks or in crevices, caves and pools from the low intertidal zone to 2,200 ft.