no piranha is a shoaling species, reds or rhoms. they simply just tolerate each other. yes they do have reds in that casino and no they didn't breed they had to eventually take out the 2 rhoms becuase of fighting. serras are different the pygo species, serra are fin nippers and pygo attack full out. so they dont mix. trust me i own 4 different types of piranha, 6.5 inch manuelli, 10.5 inch gold diamond rhom, 6 reds, 1 piyara 
