I am not a pro at S/W yet, however I don't think you can put an anemone in a 5
gal. tank. There are many kinds and maybe there is one you can but I dont think so. They are very difficult to keep along with needing very good lighting. I wouldn't even think of one in a bigger tank until the tank is well established and you really know what you are doing. I want one some day as well, but I am going to research and become more experienced first.
Is this your first S/W tank? If so, maybe inverts only to get the feel of it. I dont think a clownfish can go in a 5
gal either.
I would add another couple pounds of
LR, and a few nice inverts.
The more experienced people will verify if I am correct or not.
There is also a sub-forum under the reef forum for nanos. People there can probably give you good ideas as well