Stichodactyla is a genus of anemones. They are usually called carpet anemones. The family of Stichodactylidae named after them additionally includes the genus Heteractis. Normally Stichodactyla gigantea and S. haddoni are encountered in the trade, the difference being that Stichodactyla gigantea has longer, pointed tentacles, while Stichodactyla haddoni has round, button-shaped tentacles. Rarely represented is the Caribbean Stichodactyla helianthus, and those referred to as min-max anemones are possibly Stichodactyla tapetum, although a second, smaller form is also common here, introduced as a hitchiker on live rock. Stichodactyla mertensii is normally not found in the trade. S. tapetum is only a few cm large, S. helianthus grows to 25-30 cm, and S. gigantea and S. haddoni can have a span of up to 80 cm, while S. mertensii can grow to over 1m. So you should have enough space in the aquarium. Carpet anemones are the natural symbiotic partners of the false clownfish (Amphiprion ocellaris) and clownfish (Amphiprion percula), in which they usually enter without any problems - they would be ideal here if they did not have such a gigantic space requirement. Stichodactyla, except for S. tapetum, prefer to live on sandy bottoms into which they burrow with their foot.
They feed on light via their symbiotic algae, the zooxanthellae, but also actively catch fish with their strongly stinging tentacles - one should definitely be prepared for the possibility of other tank inhabitants being eaten by the larger species. The aquarist is also at risk, especially when the animals are hungry, which is why gloves are best worn when handling them - preferably with sleeves to protect the thin skin of the inner arms - as we can report from our own painful experience. The animals can be colored from beige to green, purple or especially rarely bright red to pink, S. helianthus is mostly beige-gray, and S. tapetum has a variety of multicolored color forms.