Looks good. You need to breed the young against each other, and you will get some more xanthics, then breed the xanthics against each other, and you should come out with 100% xanthic babies.
They're all heterozygous for xanthism though (Aa). So, if you breed two of the offspring you should get 25% homozygous recessive (xanthic) and 75% normal looking (1/3 of those will be (Aa) and 2/3 of them will be (AA)). Or if you breed an offspring (Aa) with the xanthic adult (aa) you'll get 50% xanthic and 50% heterozygous.
You should be able to tell by .5" at most if they're xanthic fry. Probaby closer to .25" (1cm).