looks like an adult mimic tang to me,i think its the same as a chocolate tang just different common names depending on what source or who you talk to. anyways i have had one for about two years, and im more than likley biased because its my favourite fish, but i would have to say its one of the stronger tangs as far as withstanding bad water quality goes.. i lost an anenome to a powerhead in my orginal tank and he was the only fish to live throught it, he grazes all day off the rock and readily accepts any food i offer him and he doesn't bother any of my other fish including the tangs(from previous tank) overall i feel its a great choice of fish but thats just me.... good luck