They aren't the best choice, ecspecially for beginners whith tangs. Not saying you are, but I am assuming you may be. There are many other choices such as the Kole tang, Yellow tang, Scopas, Mimc tang, Atlantic blue, and the list goes on. These guys would fare much better, and im sure you would enjoy a fish that does well rather than always worrying whether or not it will make it. Best of luck, and I hope you find another tang that works out. Also the chromis are a bit sensitive, I bought 6 and ended up with 3. They are doing very well, and I have no idea what happened to the other 3, but they seem to do best in odd numbers and they always school. (they didn't school when I had 6). I know my perc clowns at night always swim around near the surface this is probably your problem. Just try to mesh it off or something. Well hope you start having better luck, and hope whats left pulls through.