Before I got my new fish today, the fish I had in my 10 gallon planted tank were 9 ember tetras and 1 male endler's livebearer. The new ones I received today and joined everyone in the tank are 4 more endler's livebearers. I guess my original guy, named Hierophant Green, was used to being the only endler because he immediately started flaring at all of them and causing trouble. The four new males have been pretty much completely peaceful with one another though. Hierophant had been bullying them all day and it's stressful to watch honestly. As mentioned he's been flaring a ton, nipping, and aggressively chasing all the new guys. Only a couple of them have stood up for themselves but that doesn't keep them safe. I know this is probably normal because Hierophant sees the tank as his territory and was alone for so long, but I don't know if this behavior is going to last, I really hope not. I just want to know what to do. I don't know if I can wait it out, because these are aggressive displays of dominance, not just them figuring out their pecking order. Maybe it'll calm down after a few days? The fish have plenty of cover to hide, but should I maybe keep him in quarantine alone for a while, then reintroduce him? I don't know, I would love some help and advice.