Magnificent Sea Anemone

Radianthus magnifica

Habitat & Distribution :  attached on hard substrates, depths 0 - 20 m, Indo-Pacific Ocean

Diet : Photosyntesis results from zooxanthellae, plankton, small fish, invertebrates and suspended particles

Size: 20 - 50 cm; can reach 1 m

Lifespan: Up to 80 years

Description

They are big anemones with concentric tentacles reaching up to 8 cm long, often yellow, brown or green with lighter tips. When the tentacles are retracted, the body column is clearly visible; round, bright and very colorful, ranging from green, electric blue, red and purple.

Behavior

May be solitary or live in colonies. Solitary individuals can cluster together, making them seem like one large individual. This anemone can also reposition itself and move from one place to another, either by "crawling" with its basal disc or letting the currents carry its body away. Semi-aggressive, it can sting other anemones that encroaches on its territory.

Reproduction

Can reproduce asexually and sexually. Asexually, the parent splits itself, creating an identical clone (binary fission). Sexually, it engages in broadcast spawning, releasing gametes into the water for external fertilization.

Communication & Perception

This anemone has three nerve "nets" that controls the contraction of its tentacles in response to mechanical and chemical stimuli; the opening of the mouth (pre-feeding response); and the locomotion of the body (repositioning or escape response). When threatened by predators, it can also release a chemical signal to warn others of its species.

Predator

Other anemones, nudibranchs, sea stars, angelfish, and bristle worms

Conservation Status: Not Evaluated (IUCN Red List; 2025)