Harlequin Rasbora Being Territorial

My biggest harlequin rasbora won't let any other rasbora into the left side of the aquarium. It's a 29 gallon tank and there's currently 6 rasboras in total. This has been happening for a while, though this stopped temporarily after installing my aquaclear 70 to the tank earlier this month, it started again today. At one point there was a school of 9 though those deaths were a while ago, except one. Last Thursday, I found one of my rasboras dried up on the ground, I tested the water after that occurrence and the water was fine. Now the tank has a glass top so that can't happen anymore. Anyways, do you have any ideas on why this is happening.

 

HI there,
Sounds like you have an alpha male situation. One solution is to add more of the Harlequin Rasboras but first, what's in the tank with them?

 

It's just them and an amano shrimp at the moment.

 

It's just them and an amano shrimp at the moment.

Okay, you could add 5 more harlequin rasboras to see if that works. Usually, it should.

 

I'm definitely going to add more, but I'm not sure about adding 5 more. I still want some room to stock the tank.

 

I'm definitely going to add more, but I'm not sure about adding 5 more. I still want some room to stock the tank.

Okay lol, how about 2-3?