Stichodactyla haddoni

Before you buy: LiveAquaria rates it “difficult”: it is one of the easiest carpet anemones, but still demanding and best left to experienced aquarists. It needs a fully established aquarium, perfect water, adequate flow, intense lighting and at least 114 litres (30 US gallons). Acclimate it slowly by drip.

Setting it in: it is a sand anemone. Dig a hollow where you want it to stay and lower the flow so it is not blown away; once its foot is buried, move sand around the column and restore the flow (LiveAquaria). It sometimes attaches to the bottom glass under the sand. It may move: screen pump intakes with foam.

Danger to you: LiveAquaria lists it among the few anemones that can cause a severe reaction in humans; its tentacles stick so strongly that they tear off when you pull your hand away. According to Fautin and Allen contact is painless but can raise welts. Wear gloves.

Tankmates: its strong sting can harm corals and anemones as it moves; no other anemone within 30 cm. It can eat fish other than clownfish, and shrimps or fish that touch it struggle to free themselves.

Sensitivities: no copper. LiveAquaria lists strontium, iodine and trace elements as supplements. Loss of colour and shrinking tentacles signal an anemone in trouble (Fautin and Allen).

In the wild it feeds in two ways: through the photosynthesis of its zooxanthellae, and by catching small invertebrates, fry or juvenile fish with its tentacles, which it paralyses with its toxins.

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