I’ve kept them with Cory Catfish, Otocinclus Catfish, and dwarf shrimp before without any problems. I also once kept a Beta in a grow-out tank with about 100 young CPD’s.
Not sure if any of these choices are out-of-the-box, but they worked for me. CPD’s are very timid and just don’t do well with most other aquarium fish. Just my 2 cents…