As Peter has already enumerated are there several different ways to breed Parosphromenus.
One is suitable for the extensive method (many plants) and others for the intensive breeding method (only a few plants, some even almost “sterile”). Each type can carry on their way to success with proper execution.
I prefer the way of Martin Hallmann: no or only a few plants, bubble-filter and only one breeding pair per aquarium. Also I have more leaves in the aquariums (two to three layers) and a swamp root. As caves I use ceramic or sometimes film-capsules.
What I try in recent times is to don’t take the young fish separately in plastic boxes but in a so-called “Gerdkasten” in the same aquarium. With a smaller number of young fish to 15 it will appear to work well.
Christian Hinz