Its body is translucent white with patches of yellow and orange pigments forming five longitudinal lines. Along the mid-line there is a row of oval blotches, merging towards the rear. Occasionally individuals have black streaks, blotches or fine spots on their backs. This species is often found in large numbers.
The preferred diet consists of encrusting bryozoans, especially Membranipora membranacea , but also Electra pilosa , Callopora dumerilii , Celleporella hyalina and Tegella unicornis.