Stichodactyla gigantea

Before you buy: LiveAquaria rates it “Expert Only”: one of the most demanding anemones, for very experienced aquarists only. It needs a fully established tank, perfect water chemistry and at least 189 litres (50 US gallons) according to LiveAquaria. Acclimate it slowly by drip.

Setting it in: dig a hollow in the sand at the base of a large rock, where you want it to stay, and lower the flow while its foot attaches; then move some sand around the column and restore the flow (LiveAquaria). It sometimes attaches to the bottom glass and wanders: screen pump intakes with foam.

Light and flow: very intense lighting and strong flow (LiveAquaria).

Danger: its tentacles stick and it hardly lets go without damage. LiveAquaria lists it among the few anemones that can cause a severe reaction in humans, especially on thin skin (underside of the arms, back of the hand); Fautin and Allen note it causes no stinging sensation but its tentacles tear off in clumps. Wear gloves. It can eat fish other than clownfish and harm corals and anemones: no other anemone within 30 cm.

Sensitivities and health: no copper. A well-acclimated anemone becomes very sticky (LiveAquaria); loss of colour and shrinking tentacles signal a problem (Fautin and Allen).

Its zooxanthellae are obligate symbionts that supply much of its energy; host anemones also catch small animals that bump into them.

In the aquarium, LiveAquaria recommends feeding weekly or even daily: chunks of fresh fish, raw shrimp, large mysis and other meaty marine foods.