I agree.
A 5 gallon is too small for fish, sorry. You could have a cool invert tank with that though, and possibly some zooanthids, but that would be it. No anemone.
Upgrade to a 20 gallon and your options are MUCH bigger.
Sorry, but tank size is very important. It will take daily maintenece to keep salinity correct. Also, a clownfish needs swimming room, and a anemone needs a well balanced tank (not one that flucuates in water chemistry alot, as a nano tank does) and alot of growing room.
btw, I'm moving this to the nano-reef forum.