Neon Green Star Polyp

Green star polyps grow from a shared, purple-tinted mat that encrusts over rock, glass, or pretty much anything stationary, pushing up hundreds of eight-tentacled polyps that open in unison when the lights come on. It's one of the fastest-spreading corals in the hobby, which is exactly why some reefers keep it isolated on its own rock or frag plug instead of letting it loose in the display — left unchecked, it'll happily overgrow neighboring corals. Retracts to a bare mat at the first sign of disturbance, then reopens within minutes once things settle.

Care level: Easy · Light/Flow/Placement: Moderate light, moderate flow, bottom-to-mid tank (consider isolating) · Max size: Encrusting mat, spreads indefinitely · Diet: Photosynthetic, no target feeding required