It's really not weather you have bully fish in your display especially a 160 it's the experience level that matters not how there takin from the ocean if they made it from the ocean to a fish store in Canada then to your tank then died, it's not because the way they were handled it's the experience level of the hobbyist who purchased it weather it be not researching enough BEFORE purchasing not after , which I read in a comment here that the person research info on the dish after they bought it then put it in there tank ten it dies then they researched info on the fish that's a little ass backwards , these fish in the right hobbyist tank should flourish . Seen to many post about dead fish check your levels and make sure you have as much info on the fish before it's bought an make sure your tank will be able to handle the fish first ..... then buy not the other way around ...