[Troy F]

I think a tang/surgeon fish would be fine in a 120 depending on type but I think you'd need a much larger tank to attempt a group. I've seen the results of a group of yellow tangs kept in a medium sized tank at an office I service. It isn't pretty, the maintenance guy regularily replaces tangs (hell they're only around $20). One of the ladies their asked me one day, after I'd expressed an interest in the tank, if it was normal for the tangs fins to fall off? I of course said no and she replied that quite frequently they'd find one laying on the bottom without most of its fins.

As far as a huge school of fish like you were asking about originally, I'd say you should bring your numbers down to around 8 like Duss mentioned. The green chromis Chromis virdis stay smaller than the other green chromis C. atripectoralis.

I did a bit of research and asked around a little about some other fish such as damsels that can be kept in groups. Despite what Scott Michael's Marine Fishes says about the Pomacentrus spp. of damsels I've heard that they pretty much act like any other damsels. One account said they single one fish out of the group and pick on it until there are no fins left and then they move on to the next, leaving the other to heal.

A nice shoal of fish for your size of tank would be a small group of the Paracheilinus spp. genus (ie. flasher wrasses). I'm thinking of a group myself. One male and five or six females would be stunning if you ask me.