My plan is a 20 gallon long tank (approx 75 liters) for 10 male paros with plenty of cover and hiding spots..
The reason is I have 5 male Spec Ampah’s, one extra male Parvulus and approx 5 male Opallios, and need to get them out of the smaller breeding tanks, and it would be much easier to maintain them in one tank.
As soon as I get a good count on the females I would have a good system to provide guaranteed pairs available to those here in the US.