I am including it to show what a *healthy* anemone should look like, because mine and the large majority of anemones in many aquariums are not healthy, unfortunately. They are often sold a pure white shade that many people think is attractive, but actually this is a sign of an anemone that has lost all its natural symbiotic algae due to suboptimal conditions.
I inherited mine originally with my 55gal tank (now my 60gal tank), and learned too late about these animals. They have high lighting and water condition needs that must be met to keep them happy. This includes very good flow and completely clean water, with low nitrates. In the wild, these animals actually have no true lifespan and can in theory live forever if conditions are good, because they do not have age-programmed apoptosis (cell death) in the genetic code of their tissues.
Unfortunately, most do not last long in home aquariums, a fact that I regret not to have known before I got mine (though I got mine with the the rest of the tank equipment, rock & livestock).
Clownfish do have that interesting and well-known symbiosis with anemones (they can be immune to the sting and may use them for protection if they accept them as a matched host), but they also do not *need* an anemone host. Clowns often take to other corals and plants (mushrooms, ricordia, frogspawn, grape caulerpa and halimeda, just to name a few). Anemones do have the capability to move around the tank, so be prepared for this; they can and will sting everything in their path, including any corals they decide to sit down next to, and there is very little that you can do about controlling their movements when they get the inclination to go somewhere.
Mine has only moved twice, and I just cleared out the corals in its path and hoped it would settle down in a quiet place (eventually it did). They do have an attraction to powerheads because of the flow, which is not a good thing, because they can get caught up in them and chopped up if they choose to try to anchor on one (there are PH guards available to prevent just this sort of thing from happening). Mine was actually starting to recover its natural brown color (as shown in the photo above) and eating very well up until my tank move to the 60gal tank.
Unfortunately, it was one of the animals that was greatly disturbed and has never fully recovered. It has now shrunken down to half its size and refuses the shrimp that it once took readily. It has also lost some of its brown coloration and has decided to stay under a rock ledge, so I'm not sure what to do with it. I will certainly be sad if this beautiful animal dies, but it has been several weeks, and it has not seemed to either improve or get worse, so I am still hopeful even though it has not been eating.