Identification:
This spectacular flatworm is easily recognized by its dark green, velvety body, adorned with a constellation of small, bright yellow or white dots—resembling stars in a night sky. Its wide, undulating margins may have a fine pale outline. As with most Pseudobiceros, the body is broad and oval, with folded pseudotentacles at the front.

Size:
Up to 6 cm in length.

Habitat:
Frequently found on coral reefs and rubble zones, often near ascidian colonies or encrusting organisms.

Depth Range:
3 – 25 meters; usually observed crawling slowly over reef structures during the day.

Diet:
Feeds primarily on colonial ascidians, which it digests externally using its extendable pharynx.

Reproduction:
A hermaphroditic species known for its “penis fencing” behavior. After one succeeds in inseminating the other, both may go on to lay eggs in gelatinous clusters on hard surfaces.

Fun Fact:
The celestial look of Pseudobiceros stellae has earned it the nickname "starry night flatworm." Its warning colors indicate that it may contain toxins or be distasteful to potential predators—an excellent defense in the reef’s competitive food web.