One of the most fascinating symbiotic relationships you can witness underwater is that which exists between sea anemones and clownfish. There are 29 recorded species of clownfish, which inhabit both the Pacific and Indian oceans, particularly in reef environments between the Philippines and Australia. They range in color from shades of brown to shades of blue, and each has specific needs and preferences. Let’s take a closer look at this amazing relationship phenomenon.
The Partnership Between Clownfish and Anemones
Clownfish, which are sometimes simply referred to as anemone fish, along with damsels, which are close relatives, are the only kind of fish which are not stung by the sea anemones tentacles. This is only possible because these fish secrete a slimy mucous which protects them from the anemones they inhabit. If for some reason they lose their protective coating, they will be stung and die. Why live in such a dangerous environment? Simply put, the clownfish need the protection that anemones offer. So long as they stay in the shelter of the anemones tentacles, they are safe from predators.
Anemones benefit from this commensal relationship as well. Not only do the clownfish help to keep them clean by removing algae and leftovers, and help to keep the water around them circulating, they actually fertilize the anemones with their droppings. In addition, they chase away polyp-eating species such as butterfly fish, providing the anemones with protection.
Different Species Live Together
Various clownfish and anemones have adapted to live in symbiosis with one another, with each species of clownfish preferring a specific type of anemone. Some of the most common matches you may find while diving include:
• Percula Clownfish and False Percula, or Amphiprion Clownfish living among carpet anemones, maroon Riterri anemone, or Saddle Anemones. Both species are orange with wide white stripes outlined in black; and they rarely grow to more than 3 inches long.
• Clark’s Clownfish which is also known as the Clarkii Clown, an aggressive species that can grow to 6 inches in length, living among Sebae, Long-tentacled, bubble, saddle, or carpet anemone. The Clarkii clown is brownish orange, with a bright orange head and wide white stripes.
• Tomato Clownfish, which have a single white stripe behind the eye, and which are also very aggressive. These clownfish sometimes choose to live among coral, however they prefer Bubbletip sea anemones. They will sometimes take up residence in Sebae or Long-tentacled anemones.
• Maroon Clownfish, sometimes called Spine-Cheeked Anemonefish, which have wide white stripes on their foreheads and white stripes around their midsections. These bright red clownfish prefer purple Ritteri amenone, although they will sometimes partner with Bubble anemone or Long-tentacled anemones.
• Pink Skunk Clownfish, which is actually a peachy-pink color, with a white stripe running horizontally along its dorsal side, from tip to tail and smaller white stripes behind the eyes. Preferring Long-tentacled anemone, these clownfish will sometimes select Bubble anemone or Carpet anemone to pair with.
This relationship, along with the beauty of the pairing between clownfish and anemones has led to even more understanding about anemones. Anemones reproduce very slowly, and they can live for longer than 100 years. They are a vital part of the ocean’s ecosystem, and they are vital to the survival of wild clownfish.
Courting and Life Cycles
Male clownfish begin the cycle by preparing a nest in advance of courtship. They then court females by chasing them, nipping at them, and by extending their fins in a flashy display. After chasing a female to his nest where she deposits her eggs, the male clownfish will guard the eggs against predators. The eggs hatch very quickly – in just four to five days, juvenile clownfish emerge. Born as hermaphroditic fry, clownfish are capable of transforming themselves from male to female. This sometimes occurs when they are adults, although it more often occurs when they are still developing. A transformation from female to male is impossible, and it is interesting to note that female clownfish are both larger, and more aggressive than males are. If a dominant female dies, one of the larger males will transform into a female.
In the wild, clownfish can live for as long as six to seven years. Their habitats are threatened by global warming and coral reef destruction, as well as by unsustainable commercial fishing techniques, like dynamiting. Clownfish themselves are threatened by the demand for aquarium specimens, as are their anemone hosts and many other wild tropical fish.
A Special Note About Aquarium Clownfish
Sadly, there is a direct link between the loss of wild clownfish habitat and the aquarium trade. For a long time, aquarium keepers believed that clownfish needed anemones in order to thrive. While it is true that they do require protection in nature, there is no need for them to have wild anemones in their aquariums with them! In fact, anemone hunters are causing problems in the natural environment, and wild anemones are notoriously hard to keep in captivity. Of the thousand or so species of anemone, only ten species are capable of hosting clownfish, and their removal from the natural environment is putting wild clownfish at risk. In addition, upon their deaths, which tend to happen quickly in captivity, these anemones release huge amounts of toxins that will kill all the fish (including the clownfish) in your aquarium. A better choice for domestically raised clownfish is a captive raised Xenia, which looks a lot like an anemone and which clownfish enjoy. Keeping wild anemones in a tank benefits no one.
In addition, wild clownfish partner with their host anemones from the time they hatch. Captive clownfish are kept in fairly sterile environments prior to being sold, so they will often not even show interest in a wild anemone. This is just one more reason why aquarium keepers should never buy anemones, despite what pet store owners might say.
As you are diving, remember that clownfish tend to be extremely territorial, and try your hardest not to get too close or place them under undue stress. Do not try to capture a wild clownfish under any circumstances. If you must have a clownfish for your aquarium, don’t buy one which has been caught in the wild – choose a captive bred clown instead, and if you plan to have more than one, choose a pair of juveniles. Protecting wild clownfish and other species is both a necessity and a privilege we as divers should take seriously. Do what you can for marine life, and be a good example to others. With concerted conservation efforts, both clownfish and anemones will continue to thrive in the future.