Also known as the leathery sea anemone, the purple tip, blue tip or the long tentacle anemone, the sebae is among the largest anemone species dwelling the Indo-Pacific region. Widespread in the coastal areas around Africa to Australia, Polynesia and the Red Sea, these creatures prefer the shallow waters in reef areas not deeper than 40 m where they can cling to corals.
The oral disc of the anemones is flared and can grow to a diameter of 50 cm. The number of the tentacles is usually a multiple of six, but not more than 800. They are long, usually around 15 cm and they end in a rounded, colorful tip. The tentacles are arranged around a central oral cavity and are usually grey, greenish, violet or tan, they have white, wart-like dots, but they otherwise have smooth texture and leathery appearance. Sebae anemones can also be of uniform light grey color as well. The animal gets its coloring from the zooxanthellae algae that live inside its tissues, but the algae are not the only life forms that sebae anemones live in symbiosis with – the large disc and the long tentacles provide home for over 15 different species including fish and shrimps. However, this anemone species uses advanced techniques to deter animals that are harmful or dangerous – the tentacles have cells called nematocysts that secrete venom, making the sting of the anemone painful.
These anemones, like most other species of true anemones, use two feeding methods: they extract food particles and capture tiny prey such as miniature shrimps and other crustaceans from the water column with the help of the tentacles and they also use the waste produced by the photosynthetic zooxanthellae algae inside them. The mouth in the center opens only when the animal is feeding – when it is not hungry and searching the water column for food, the mouth is sealed.
These anemones have two reproduction methods as well: they can either multiply asexually, by means of a fissuring into two separate individuals (a process called scissiparity) and sexually. When the latter method is chosen, the male and the female release their respective gametes into the water simultaneously. Fertilization occurs externally, the fertilized eggs soon hatching into larvae that grow to form new sebae anemone individuals.