[ngrubich]

I've read that they prefer softer water when breeding. There used to be a site (dwarfpuffers.com) that had a ton of info, but I can't get it to work anymore. I wonder if it was shut down or is just being worked on at the moment.
At any rate, check out this website for some cool info on breeding:
http://www.zwergkugelfisch.de/deu-dwarfpuffer.htm