Wow. A tang in a 16 gal? What kind of tang?
You can only have 2 clowns, You can only prob JUST get away with having clowns in that tank. 3 clowns, When one becomes a female, The female will kill the male it does not like. Or they'll all fight to become a female. Either way, One needs to go. If you have 4, In a 16gal tank. Things will be worse.