
Source: Wikimedia Commons
Stichodactyla mertensii
Regarded as the largest sea anemone, at over 1 m across. Its oral disc is more ovoid than circular, contours to the surrounding substrate and attaches by adhesive wart-like verrucae. The tentacles are short, only 1-2 cm.
Stichodactyla mertensii is widespread across the tropical and subtropical Indo-Pacific, from Mauritius to Fiji, from the Ryukyu Islands of southern Japan to Australia, and in Hawaii. At over 1 m in diameter it is regarded as the largest sea anemone; the next largest, Radianthus magnifica, has longer tentacles. The oral disc is more ovoid than circular, contours to the surrounding substrate and is attached by adhesive wart-like verrucae. The tentacles are uniformly shaped, blunt or pointed, and only 1-2 cm long. It contains obligate symbiotic zooxanthellae. It can be confused with Stichodactyla gigantea and S. haddoni, but is most easily distinguished by habitat: those two prefer sand while S. mertensii prefers rocky or coral substrate. It hosts at least 13 species of anemonefish, about half of all species, plus the threespot dascyllus.
Source: Wikipedia (CC BY-SA 4.0)
The Merten's Carpet Anemone grows to Oral disc over 1 m, tentacles 1-2 cm.
The ideal temperature for the Merten's Carpet Anemone is 22〜26℃.
Origin
Tropical and subtropical Indo-Pacific, from Mauritius to Fiji, from the Ryukyu Islands of southern Japan to Australia, and Hawaii
Size
Oral disc over 1 m, tentacles 1-2 cm
Temperature
22〜26℃
Sources: LiveAquaria (care parameters listed for its sea anemones) / SeaLifeBase
Edited & verified by: BreederDirect editorial team
The taxonomic, regulatory, and husbandry data on this page are compiled and verified against the authoritative primary sources below.
Accepted name: Stichodactyla mertensii Brandt, 1835
Synonyms: Actinia (Isacmaea) gigantea (Forskal)
Authority databases: WoRMS
Nomenclature follows global taxonomic authority databases.
Sources: CITES Appendices (species not listed)
Regulations may change. Always verify the latest information with the relevant authorities.
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Nutrition from symbiotic zooxanthellae, supplemented about once a week with meaty foods such as fish, shrimp and clam.
It carries obligate symbiotic zooxanthellae and does require illumination.
Unlike its sand-dwelling relatives it attaches to rocky or coral substrate and spreads along the contours of that surface.
Keep it within the care parameters LiveAquaria lists for anemones of this family: 22-26C and a specific gravity of 1.023-1.025.
Besides photosynthesis, offer meaty foods such as fish, shrimp and clam. The oral disc is large, so place food at several points.
At over 1 m across it needs a tank sized for the footprint it will eventually occupy. It is easily confused with the related carpet anemones. It is not listed in the CITES Appendices.
Advanced. This is an advanced-level species. It requires specialized equipment and advanced husbandry skills with precise environmental control.
The ideal temperature for Merten's Carpet Anemone is 22〜26℃. Avoid sudden temperature changes and maintain a stable environment.
Merten's Carpet Anemone typically reaches Oral disc over 1 m, tentacles 1-2 cm as an adult. Size may vary depending on care conditions and individual genetics.
Merten's Carpet Anemone feeds on: Nutrition from symbiotic zooxanthellae, supplemented about once a week with meaty foods such as fish, shrimp and clam.. Aim for a balanced diet with appropriate feeding frequency.
The price of Merten's Carpet Anemone varies significantly depending on variety, size, and individual quality. Check our market price page for the latest pricing information.
Last updated: September 16, 2026