oh, to be more relevant to the rest of the thread. Someone mentioned how piranhas will coexist with SA cichlids and such; It shouldn't be too much of a problem as long as you don't keep a school of piranhas. Piranhas tend to be a bit on the shy side and might actually give way to the bigger oscars, pacu, dempseys, etc. BUT if you give a piranha 4-5 buddies, their strength seems to lie in numbers, then I would fear for your oscar's life!!! =P