dovii, umbee, motag, beani.............. its really hard to tell who is the most aggressive, everyone has their own experiences, mine are not in that order, but one guy said that his blackbelt beat up a dovii, thats one dovii, oscars shouldn't even be in this discussion, convicts have more of a right, even neets. this question is psoted on evry cichlid forum in the land like every two months the evidence is inconclusive to reall say who is the baddest. it is all personal experiences. I'v e had a dovii that ripped the **** out of some RT's and midas', they were all a foot long or bigger. Now as far a blackbelt i would love to see a full grown alpha male swim with a 14" + dovii, umbee, motag, haitensis, RT, or Midas, etc....... Blackbelts don't have what it takes, i had one and a Jack Dempsey picked on it, but then again that is my experience, and i've only had one, and from what i've heard many people have said comperable things to what i've said