2 Black Skirt Tetras bullying others?

Hello all, so I am having a problem with my Black Skirt tetras. I have 4 of them and two of them have become very aggressive, they bully the other two docile ones, and have seem to set up their own boundaries in the aquarium. I have had the 4 of them together for almost 2 years without any problem, just now they started to act like this.Will adding 2 more black skirt tetras fix this? Other tank mates are 6 red minor tetras. I have a 20 gallon tank with and heater and eheim 2213 filter system.

 

Adding fish may solve the problem in two ways, they become comfortable with a larger school and decide a pecking order or the bullying is split between the 4 other black skirts.

 

So right now my best option is to get more black skirts?

 

Welcome to fishlore!
Yes, the best option is to get more.

 

Sounds good, ill pick up some more tomorrow! Thank you guys very much, ill check in later and tell ya how they are doing

 

I agree, grab more so they "school". I had whiteskirts and they were JERKS, added more and things evened out a bit.

 

Agree I had 7 and they got along fine with each other and others. They will nip flowing fins just an FYI and when you buy them there very susceptible to mouth fungus and have seen them with it in tanks in fish stores so make sure the mouths are clean and make sure they don't give you any. Don't know where you get your fish but most let them swin around and will sell them as opposed to fixing them. It's not contagious but hard to get rid of. Just an FYI