Matt, Its not the hakari in general that is the problem, just some fish tend to get agressive I found when I feed it. My one red spot in particular will chase everything in the tank if he gets Hakari, the other one not bothered at all. The rotkeils & gold have no aggression on hakari but my Belem's try and kill each other, same with the oscars one is fine the other not. I cut it out of the feed altogether and the aggression with the few stopped, it just seemed to be one of those strange things!