Cr. noto's are a blackwater species ... come from the same area and water as Heckel Discus. While I could keep them fairly easily in 6.8 pH soft water with twice a week 30% water changes, breeding will take Heckel like stats ... pH 5.8 or lower, no detectable hardness, probably peat to boot. Mine never even showed any sort of pairing behavior. Had two males and two females. Dithers help, these were much more shy than say Cr. compressiceps. Mine hid all the time, even before I added what later turned out to be a psycho Laetacara thayeri. A 75 should be fine for buying a group and letting them pair off. I'd go larger if trying to force pair a random male and female though. These fish do not like each other.
Cr. regani comes from a lot of differant river systems, so it will partially depend on which race you have. Don't mix races, as one as already been seperated into it's own species, though still underscribed (Rio Xingu race). Most are clear or white water rivers though, so didn't need the ultra low pH or hardness. Also less aggressive so pairing should be easier (am guessing since have never located any yet.)
