So I realize that some of you don't have huge tanks to house some of the tankbusters that some of us house... here is a good idea for the noob looking for a mean guy for their lil tank... try a school of spotted puffers. At the LFS I work at when people want to put puffers in their comm. tank and don't believe me that they are aggressive I just throw a goldfish in there and they just eat it up right away... plus they are kinda cool looking...