Poor green chromis

[stryder]

I just bought three green chromis yesterday and all were doing well, eatting swimming and the like. (I only have two clownfish otherwise and they are very nice fishys) But this evening one seemed to have lost some scales on his tail and was in a daze not wanting to eat. he now looks like he is about to die lieing sideways on the gravel. I did just notice one other of the chromis being kinda mean to the other (chaseing and nipping). Do you think he hurt the other chromis enough to kill him? And should I take the mback if he is just going to kill them off? (I wanted them for a school) Thanks!!
Stryder:notsure:

 

[gregvabch]

it's possible, maybe you've got two males and a female, the larger or more aggressive male could be letting the other one know that he's not welcome and he could end up killing him.