Please read this about raising fry. They mention raising the temp which I forgot to mention. The temp breeders in the US have their fry tanks in is 80F and the adults at 70-75.

Fancy Guppies UK - Fry Collection & Development

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GUPPY STRAINS I'M BREEDING:

Blue Grass
Blue Grass Swallow
Metal Blue Grass Swallow
Red Grass
Red Grass Swallow
Neon Blue Giessen/Ribbon
Japan Blue Blue Grass
Japan Blue Wild
Neon Blue

Strains I developed in my fish room:

HB Yellow (own line)
Platinum Pink Blue
HB Blue Leopard
HB Leopard Multi
HB Red Crowntail