Ritteri Anemone

• It is the second largest anemone in the world, with an oral disc up to a metre across in exceptional specimens.
• It eats small invertebrates and young fish, along with nutrients produced by symbiotic zooxanthellae.
• It resists cellular ageing remarkably well, with documented individuals over 60 to 80 years old.
• It is the largest of the anemones that host clownfish and one of the showiest: its column is an intense magenta, blue or green, and often shows beneath the disc of tentacles.
• It hosts more than ten species of clownfish, more than any other anemone, and a single specimen can shelter an entire group.
• It closes into a compact ball when it feels threatened or at night, hiding its tentacles completely, and its clownfish are left without shelter until it opens again.
• It reproduces by fission: it splits in two, so a group of neighbouring anemones may in fact be a single cloned individual.
• It harbours zooxanthellae and depends on them, so it bleaches as the water warms just as corals do; and when it bleaches it loses its fish.
• Collection for the aquarium trade has reduced its populations in accessible areas, and it is difficult to keep in captivity.

Skeleton type

Invertebrate - no skeleton (soft-bodied cnidarian)

Habitat & environment

Coral reefs of the tropical Indo-Pacific, from the Red Sea to Polynesia, in shallow, well-lit water

Birth weight

Microscopic planula larva after fertilisation

Size at birth

Microscopic planula larva after fertilisation

Litter / clutch size

Numerous eggs and sperm released into the water at once (sexual reproduction), alongside asexual reproduction by fission

Sources consulted: Animal Diversity Web; CreationWiki; MonsterFishKeepers; Seaunseen; Reeflings Care Guide; Animalia.bio; A-Z Animals (sea anemone); Bay Nature; AnimalFact.com