Hi everyone please help!!!!!! We have 3 Columbian red fin tetras but the biggest one is such a bully, he chases all the fish in the tank and sometimes it gets to the stage where the other fish just hide in the plants, its heart breaking to see. I put a mirror against the side of the tank and for a short while it was busy posing and fighting with itself but the novelty wore of, i tried removing the mirror and then a few days later putting it back but this is a clever fish not to be fooled it worked it out. Any suggestions please on how to deal with this? Desperate.