I have had my Singapore Angel in the tank for 1.5 years and it seems very healthy. Although I've been told these fish are hit and miss in aquariums as their health can be problematic. My semi-aggressive tomato clown doesn't bother it, but they were added at the same time. It is very docile, and if your Tangs are aggressive it could very well be a problem, but of course you never know until you try. Good luck.