guppie fry

Recently I’ve found 2 guppy fry in my tank that have very large stomachs and a red almost blood coloured line on the stomachs, I’m not sure what it is and can’t find an answer when I search for it. It looks like defect and it’s making it hard for them to swim. Any help would be appreciated.

Looking to breed guppies to try breeding for profit. I have a 29 gal somewhat heavily planted tank lots of stem plants, substrate fully covered, salvinia covers almost entire surface. I was wondering if it would be possible to breed 24k gold guppies from a single pair or trio. Would the later...

Just picked up the Fluval Multi-Chamber Holding and Breeding Box and was wondering if it will be too cold in the box for guppie fry? I have a 100watt Eheim heater in the tank set at 79 degrees.