Just got these on Tuesday. There is 10 4 inch or so Caribe Piranhas. I just finished the outside woodwork on my 180 gallon tank. The sump is 75 gallons.
I got them from Jeff Rapps (Tangled Up In Cichlids) for $50 each but he threw in 2 free so say $40 each. The tank is 6'x2'x2'. Yeah I hope they grow real fast!
I forgot to mention that there are at leat 14 Exodon Paradoxus in the sump. I have a whole setup with aggressive little fish! The Exos are beasts too. I am going to get 30 more and I will be done buying fish for a while. There is a Raphael Catfish in the 180 too. The Caribes don't mess with him at all so far.