Anemone Fish are a relative of the very large Damsel Fish family and there are about 30 different species of anemonefishes worldwide. The largest can reach a length of 18 centimetres while the smallest barely reaches 10 centimetres.
They live a symbiotic relationship with various anemones which means the sea anemone protects the anemonefish from predators, as well as providing food through the scraps left from the anemone's meals. In return, the fish defends the anemone from its predators, and cleans it from parasites. The anemone also takes all the available nutrients from the anemonefishes excrement and provides a safe nesting site for them. Clownfish and certain damselfish are the only species of fishes that can avoid the potent poison of a sea anemone. Some anemonefish will only be found with one type of anemone, but others can live with many types. Whatever type they are though, you will rarely find them very far away from their chosen anemone.
In Koh Tao we are graced with three different types of these exquisite little fishes, the commonly seen Pink-Anemonefish , the territorial Saddleback-Anemonefish and the famous Clark’s anemone fish .
The Pink-Anemonefish - Amphiprion perideraion can be seen on nearly every dive site here. The top of Chumphon Pinnacle is actually covered with a carpet of lovely little creatures busy cleaning and protecting their anemones.
They can grow up to 10cm and are pink or pale orange colour with a white band down each side behind the head and a white stripe down the back and they have a white tail. There is usually one adult pair and several juveniles and they are normally seen in the anemone Heteractis magnifica. They are difficult but rewarding to take photos of, because they are always hiding or moving around their anemone home.
The Saddleback-Anemonefish or Saddleback clown fish - Amphiprion polymnus normally lives on Haddon's carpet anemone - Stichodactyla haddoni and is frequently seen at dive sites such as Pottery Pinnacle or Sairee Reef. The Saddleback grows up to 12cm and its body color can vary from orange to brown or black. It has patterns of white bars and a large white stripe from the forehead to the chest with white patches on the back, saddle, and tips of the tail. It has the most distinct swimming motion of all anemonefish , which is an up and down bobbing motion.
This anemonefish is highly dependent on its host for protection but the female also needs a hard structure to deposit her eggs on. These are often in short supply around sand-dwelling anemones therefore these innovative little fish will drag suitable materials close to the base of its host anemone. These items can be things such as shoes, pieces of plastic, cans and coconut shells. They are a beautiful subject to photograph if they stay still long enough though be warned they can be very territorial and the largest fish in the anemone will often try to deter to divers by trying to attack the divers face mask.
The Clark’s Anemonefish -Amphiprion clarkii (also known as the yellow-tailed clownfish) is the only Anemonefish known to live with all host anemones. It is variable in colour and can grow up to 15cm. It has two white bands - one behind the eye and one above the anus and usually has a third bar at the tail base with a white or yellowish tail fin. They are normally found in pairs or family groups and our resident Clark’s anemonefish family can be seen at Twins dive site where it is protected by a large stone “fairy ring” around the anemone. If you look carefully you can often be fortunate enough to see the tiny babies of the family and if you are patient you can get some lovely photographs of the group.
The Anemonefish is protandrous hermaphroditic which means if the female dies or disappears, the male will become the new female and another sexually immature specimen will quickly develop into a reproductive male.