Identification:
Euryleptid flatworms are part of the family Euryleptidae and are among the most visually striking marine flatworms. Their coloration varies by species but often includes vivid patterns of stripes, spots, or bands in yellow, blue, purple, or brown. Two short pseudotentacles (ear-like folds of the anterior margin) help in species recognition and may resemble tiny horns.

Size:
Typically between 1.5 cm to 5 cm, though some can reach up to 8 cm.

Habitat:
They are most commonly found on coral reefs, rocky substrates, and rubble slopes, often under dead coral heads or hiding in crevices during the day. Some are more active at night.

Depth Range:
Usually seen between 1 – 25 meters, although they can live deeper.

Diet:
Carnivorous, feeding primarily on sessile invertebrates such as colonial ascidians, bryozoans, or small crustaceans. They use a reversible pharynx to ingest prey.

Reproduction:
Hermaphroditic, like most flatworms. Mating can involve reciprocal sperm transfer, followed by the laying of flat, transparent egg capsules on hard substrates. Development is typically direct (no larval stage), but this may vary.

Fun Fact:
When swimming, Euryleptid flatworms resemble underwater butterflies, gliding gracefully through the water column. Their bold patterns are thought to serve as aposematic (warning) coloration, signaling toxicity to potential predators.