Harlequin rasboras aggressive?

[thecandiedfish]

So I have 5 of them in a 20 gallon and there ”chasing” is getting worse/more intense. it’s lightly planted cause the plants are new and there’s a few caves and a huge piece of spider wood. I have 1 honey gourami,5 harlequin rasbora,3 ottos,1 bn pleco,1 mystery snail and a bamboo shrimp. They all seem fine with each other but should I remove the rasboras? I like them but i don’t want them to potentially hurt one of my other fish either on purpose or on accident chasing each other. they even did that circle motion a few times where 2 fish chase each other in a tight circle.
ammonia 0
nitrite 0
nitrate 10ish
ph 6.8-7

 

[Essjay]

It's probably because there aren't enough of them. Shoaling species need at least 10. Mine don't bother each other but then I have somewhere around 15 to 18 (impossible to count them all). But you are quite heavily stocked with the fish you already have.
How long have you had them?

 

[xxEMOxLIZZARDxx]

You need to add more. They are schooling fish and need to have like 10-15 in a group.

Although I also believe that your tank *might* be overstocked.

 

[AdoraBelle Dearheart]

If you plant the tank heavily with fast growing plants, and filter well, you might be able to get away with a full school of harlequins, I think. Although would be much better, bioload wise, without the pleco.