I've gotten tips from experienced breeders just to starve them and they will eventually eat... However I'm sure you don't want to wait that long so you can get them up to breeding size...
I'm pretty new to balls, (just picked up my collection a few months ago).. All of mine switched over without too much of an effort. They wouldn't take at first then just started pounding them...
Attempt to feed em, if they don't take wait a week, try again..
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1.0 Het Albino Burm
1.0 Albino Ball
1.1 Pastel Balls
0.1 Spider Ball
0.2 Het Albino Balls
Seeking bigger cages for the family 