Mertens' Carpet Anemone Care Guide
Stichodactyla mertensii is regarded as the largest sea anemone, attaches to rock, and hosts about half of all anemonefish species.
Compiled by Aquairi from published sources · Published · Updated
Overview
Stichodactyla mertensii, Mertens' carpet anemone, is regarded as the largest sea anemone, with a diameter that can exceed 1 m. The oral disc is more ovoid than circular and contours to the surrounding substrate. Its tentacles are uniformly shaped, blunt or pointed, and only about 1-2 cm long.
Taxonomy
- Family: Stichodactylidae
- Genus: Stichodactyla
- Scientific name: Stichodactyla mertensii
- Authority: Brandt, 1835
Habitat
Unlike sand-dwelling relatives, this species attaches to rocky or coral substrate using adhesive verrucae (wart-like projections). It is distributed across the Indo-Pacific from Mauritius to Fiji and from the Ryukyu Islands of southern Japan to Australia, with reports extending to Hawaii.
Tank requirements
- Minimum tank volume: 400 L
- Temperature: 24-26 °C (75-79 °F)
- Salinity: 1.024-1.026 SG
- pH: 8.1-8.4
- dKH (alkalinity): 8-11
- Lighting: strong reef lighting for obligate zooxanthellae
- Lifespan: very long-lived (5-100+ years)
Diet
The anemone hosts obligate symbiotic zooxanthellae and relies heavily on photosynthesis, supplemented by capturing prey with its tentacles. In aquariums it accepts meaty foods such as mysis offered roughly once weekly.
Compatibility
It hosts roughly half of all anemonefish species (at least 13 documented), plus the damselfish Dascyllus trimaculatus. Specialist partners such as Amphiprion fuscocaudatus and A. latifasciatus are found only with this species. Butterflyfish and angelfish may nip at the anemone and should be avoided.
Stichodactyla mertensii (Merten's Carpet Anemone) Breeding & Propagation Guide
Overview
Stichodactyla mertensii is regarded by Wikipedia as the largest sea anemone, with a diameter exceeding 1 m. It attaches to rocky or coral substrate across the Indo-Pacific from Mauritius to Fiji. It contains obligate symbiotic zooxanthellae and is a highly generalist host to around half of all anemonefish species plus a damselfish. Its short 1–2 cm tentacles and immense size frame any propagation discussion.
Reproductive Mode
As a sea anemone, S. mertensii can in principle reproduce both sexually and asexually. Wikipedia's general account states that males release sperm to stimulate females to release eggs, with fertilization in the water column or internally, and the resulting planula larva drifts before settling and metamorphosing. No captive spawning method specific to this species is documented in the consulted sources.
Asexual Propagation
The asexual options of sea anemones are longitudinal fission into identical clones, the rarer transverse fission, and pedal laceration, in which fragments from the pedal disc regenerate into clones. Such large host anemones divide only occasionally, so deliberate fragmentation is not a practical or recommended propagation route.
Sexual Reproduction
Sexual reproduction is broadcast and pelagic: gametes are released into open water and planula larvae drift in the plankton before settling on rock. This open-water larval stage cannot be reproduced in an aquarium, so home sexual breeding of S. mertensii is not feasible.
Common Challenges
Its eventual size demands a very large reef with strong light and rock for attachment. Given the pelagic larval phase and infrequent division, the realistic aim is long-term health of a single specimen rather than reproduction.