Salt water tank maintennance?

Hi all - we've recently set up a salt water tank. It's my strong belief you should never keep animals in any level of discomfort - so am trying to be very careful not to overstock. We have a 160L tank and currently have two clown fish, one pacific blue tang, two anenomes (can't spell that to save my life), two corals, five snails and some live rock along with some weeds to hide in. I'd love to get just one more fish - do readers feel that is advisable? Also, re: the behaviour of the tang - we got the 1st anen... whatever and clown fish first and waited an additional week before introducing the corals/tang/anem... erm. We're reliably informed our water quality is excellent. We have a thriving colony of salt water fleas etc. My point - when introducing the clown fish they behaved as I'd expect an animal to do when abruptly placed in a new environment - they stuck to the centre of the tank where they could easily hide and ate pretty sparingly at first. The tang, however, - it occasionally hides in the weeds but alternates with frenzied swimming up and down the length of the tank in a bobbing fashion as if it were surfing non-existant waves. I was somewhat worried about the amount of food to provide, expecting the tang's appetite would be minimal at first - but I increased the amount of frozen brine shrimp by 1/2 regardless when I fed my pets tonight. The tang immediately chowed nearly all of it (poor clown fish!). I'm very surprised by the tang's enthusiasm, and mildly concerned the fish may bully the clown fish as it becomes more settled. Any advice?