i know a shoal can make short work of the cons, but im tellin you guys, theres so much goin on in the tank its hard for them to want to. i kno piranhas are unpredictable but still... i got 9 piranhas fighting eachother, a butti thats punking each n every one of the piranhas so there goin in circles fighting eachother and gettin bit by a butti at the same time. i got an oscar up above them swimming like an alien that has them thinking "wtf is that". then a rock structure in distance with 2 lil cons in the middle of it. they only popout to defend a lil bit then bam, back in the structure. the cons are not afraid and the piranhas are more used to eating pellets at the top of the water then eating live because this is what they were raised on from fry. the nip but i havent lost any fish to them yet. ill let u guys know the outcome.