I've never really had any trouble feeding P's although my RBP & Rhom are more shy about feeding then the Mac. I got an extermely unsual fry batch about 2 mo ago - Siamiese Tiger Dats. Trying to get them to eat was like pullin' teeth, they were dying fast until I used just born Mollie fry to get them goin'. I tried flake, brine, and micropellets - they wouldn't touch it. After a few weeks of mollies they're eating small krill chunks and talapia chunks. These guys are SUPER small maybe the size of a dime. With Rhoms, they do generally eat the fins off of other fish as juvi's. I can only speculate as to why. Perhaps in the case of my Dats their teeth may not be fully developed enuff for them to rip and tear. The Dats are far from the only fish that I own that needed weened - If I were in your shoes I'd get some very small tetras, guppies if tetras aren't doable, and see if they'll except live foods - then ween them after they start eating daily.