Mertens' carpet anemone (Stichodactyla mertensii) care guide

Group
Corals
Other names
Mertens carpet anemone, Giant carpet anemone, Sri Lanka carpet anemone
Family
Stichodactylidae
Origin
Indo-Pacific, from East Africa to the central Pacific
Water
saltwater
Temperature
22–26°C
pH
8.1–8.4
Hardness
dKH 8–12
Care level
expert
Reef safe
with_caution
Lighting
High
Flow
Moderate

Care

Stichodactyla mertensii is one of the largest carpet anemones, with a flat, wavy disc covered in short, sticky tentacles. It can grow to about a metre across in the wild. Colours are tan, cream, green or purplish. It needs a large, mature, stable reef with high light and plenty of rock and sand. LiveAquaria lists its relative, Haddon's carpet anemone, as difficult in care with high light, medium flow and bottom placement. S. mertensii attaches its foot to rock rather than burying in sand. Water: LiveAquaria gives dKH 8–12, pH 8.1–8.4, specific gravity 1.023–1.025 and 22–26 °C, with iodine and trace elements. Note: LiveAquaria covers only a relative, so the figures above are from that page, not from a source on this species. Not CITES-listed. Sources: LiveAquaria (liveaquaria.com/products/haddons-carpet-anemone). Checked October 2026.

Diet

Photosynthetic, but it needs regular meaty foods: chunks of fish, raw shrimp and other marine foods weekly or more often.

Breeding

It does not split in aquariums and is not propagated in the hobby.

Compatibility and tank mates

Aggressive. Its sting is strong enough to harm corals and kill small fish, so keep it at least 30 cm from corals and other anemones. Cover pump intakes. It hosts several clownfish, including Clark's clownfish.

Last updated 8 October 2026. Community-edited care guide on Aquatic-Auctions.

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