My CPDs are in a 29g planted tank, lots of plants/moss/rocks/wood for fry to hide and grow in. So I thought. I would always see a few fry swimming around in the moss but a few days later nothing. I finally got frustrated of this (never a fry to adult) and decided I would siphon any fry I could find out and into a grow out tank. Again, easier said than done. Turns out netting them with a small fine mesh net is the best and simplest method IME.
I now finally have fry in my grow out tank. Only 6 so far, but I got them before the other CPDs did!
Thanks,
-jim