IMO, they are meaner than the malas in general. Obviously, it depends on the individual fish also. My Aimara Wolffish is about 8" and I have no doubt that it would attack and try to kill ANYTHING that I try to put into the aquarium with it. As soon as my house and fishroom are finished shortly, I will have multiples of each Hoplias species including the curupira. I really believe that the curupira can be kept in a community tank. But, it depends on the individual fish, tank size, and other fish it's housed with. If it were my fish, I'd keep it solo. I think that is what the other person who posted meant also. Such a nice fish, I'd hate for it to get wounded or killed by another fish or for it to do the same to others as well. I think that they have a great personality, and are cool enough to warrant a tank pretty much all to themselves. Just my humble opinion. Send some more pictures please. Maybe some close ups. Thanks