They definately need soft water and ph of 7 or lower to breed
Remember to add the almond leaves and remove your carbon , you need the tannins to leach into the water and make it a tea colour , these fish are mostly wild caught (or first generation wild caught) at the moment so are do better with the black water enviroment
I have 8 imbellis and they are doing well although a quick word of warning - they do not accept flake food or betta pellets at the moment so my imbellis and rutilans are having live,froxen and freeze dried food as this is all they'll accept for the time being
They are thought to be a friendly fish but there i have still witnessed some aggression between the males - sorting out the alpha i think ,