I have not had a tank smaller then 15 gallons in 30 years.
I breed my plecs in 15's or 20's.
Don't think i would try in less then a 10.
its much harder to keep water quality up in smaller tanks, they shift quality wise nearly instantly.
So in that small tank, plop on a high powered filter, it will give you the current they love anyway.
And make sure to keep up on weekly if not twice weekly water changes for that small tank.
Queens love high current, meaty foods, and warm temperatures.