Identification:
This eye-catching flatworm displays an intense cobalt or royal blue coloration, often with electric blue or purple undertones that shimmer in the light. The edges of its body are usually outlined in a thin, pale margin—white, cream, or even yellowish. Unlike many Pseudoceros or Pseudobiceros, its surface is smooth and lacks prominent markings or patterns, giving it a clean, vivid appearance.

Size:
Up to 2.5 cm long.

Habitat:
Spotted gliding over dead coral, rubble, or rock surfaces, especially in areas with encrusting organisms like sponges and tunicates.

Depth Range:
3 – 20 meters, often found in shallow lagoons or reef slopes.

Diet:
Feeds on sessile invertebrates such as colonial ascidians or small sponges, using its extendable pharynx to externally digest prey.

Reproduction:
Like other polyclad flatworms, it is hermaphroditic and engages in reciprocal mating. Fertilized eggs are laid in clusters, often in sheltered spots.

Fun Fact:
The dazzling blue of Cycloporus venetus isn’t just for show—it serves as a warning to predators that this little flatworm might taste unpleasant or contain chemical defenses, a classic case of aposematism in reef environments.