red devils,midas,festae,dovii,umbee,jags,blacknasty,mayans,texas,trimacs. not in any order. if your looking for aggression any of those is your canidates. if your not stay away from them.
exactly what he said but a lot of the time it depends on the fish's personality. i had a texas in with tinfoil barbs half his size and he never touched them while my oscar which is half the size of the barb goes after him on a daily basis
A few other extremly aggressive fish you probably have to keep by themself are C. altoflavus, C. myrnae, C. nanoluteus, H bocourti and most Geo's. Watch your fingers if you own any of these fish.