My only concern is stunted growth from mistreatment from previous owner. All he knew about piranha's was from a book that told him coloration determined sex. He had the 4 in a 40 gallon...I think the dims. were 30-36(notsure)X13X13
In my 80 gallon I have 13 reds ranging from 5"-7 or 8" for my largest. Also in the 80 there is a little red belly who loves to hang out underneath my overflow box for my wet/dry. They will be moving to my 180 once I receive it and get it cycled. I have a 4" Altuvei which will be going in the 80 and I plan on putting a divider in the 80 gallon tank and purchasing a rhom to share the divided tank.