well yea of course you can another guys going to be doing a 10g with 2 clowns
personally i would do a pair of clowns and a firefish because 10g is perfectly fine for a pair of ocellarious clowns so with the extra 4g im shore you could fit something else
I have a clarki with a BTA in my 8g... works like a charm. I must say though,I kind of wish I had it in my 29 cube with the larger BTA. The clarkii in the 8g is really big and the anemone sometimes closes up due to over activity from the clown. I might just buy a smaller clown for the 8..