Nice looking tank,its off to a fabulous start it appears. Judging from the pics I will assume that you have Halide lighting, but maybe its the setting on the camera.
About that Anemone... In a tank that small its not really advisable for a number of reason only a couple of which I will touch on here. None of the Anemones that these clowns will host on in the wild have great success rates in shipping and then adapting to an aquarium. According to Joyce Wilkersons book Clownfish, they will host on Bubble Tips in captivity pretty redily and this is the easiest of the host anemones to keep in a tank. Keeping them in a nano though will present a few issues. You will for one have a species only tank...Clownfish and Anemone. Everything else will take a pounding from the stinging of the Anemone. Anemones in Nanos dont always fair well either due to the small water capacity and the propensity of the water quality to fluctuate considerable during the course of a day unless you have a Auto Top off system in place. The other hazad to your Anemone in a tank this small is all water intakes will have to be screened off with sponge sleaves or sooner or later you will end up with a moving Anemone finding a water intake, being sucked into it and becomeing "Anemone Puree" when it makes contack with the impeller of the pump. In a Nano this will likely result in a total and likely complete crash of your tank.
There are better alternatives as they will readily host in a number of other corals that are much more suitable. For example Xenia is one of the more common corals as is Anthelia (sp?) that will substitute as a host not that one is really needed for breeding them. They will stake out an spot and lay eggs irregardless of a host or not. Other corals I have used are larger Leather corals, Hammer, Torch and Frog Spawn just to name a few. The key is to have a colony large enough that a Clown fish wallowing in it wont make it completely close up or retract its polyps allowing it to still thrive despite the irritating clowns messing around in it. This is a far more preferrable alternative to an Anemone.
Here is you some "spiritual enrichment" you might not have seen that supports the above.
False Perc Clown
HTH's