My CPD’s were living in a 5-gallon (glass, “normal” shape) for quite a while, with plenty of plants, wood, and dark sand with a sponge filter. I had 4 adults and 8 juvies (bought, captive bred, not bred by me.) As They pretty much hid, ALL the time, and only nervously came out to eat. They had some dwarf cories in there with them, as dithers, but it didn’t make much of a difference.
Between the juvies growing out, and the fact I was ready to add 3 more adults I’d had in quarrentine, I moved the whole lot of them last night. They went into a 10-gallon glass tank, with the same plants and wood, on a substrate of eco-complete planted tank substrate and the same sponge filter, hooked into a slightly stronger pump. I don’t know if it was the larger space, or the new 3 finally brought the numbers up to where they felt comfortable, but they’ve been in the new tank less than 24 hours and they’re shoaling about the tank, all over the bottom 6 inches, like I’ve NEVER seen them do in the months I’ve had them.
All I can really say is “wow”. They’re a beautiful little fish when I can only get a peek at them at feeding, but they’re just SPECTACULAR shoaling out in the open.