here is a disaster I have never had before.
Female gold guppy had fry about 6 weeks ago.
Gradually became larger and looked pregnant as expected but at 35 days had not delivered and was in obvious distress. Measures taken to encourage delivery.
Then she blew up and started to pine cone also red streaks on flank so started some furan 2. Fish goes into labor and delivers some very underdeveloped live fry as well as multiple eggs with eyes.
Fry survive for about 1/2 hour then die except for a couple who are still living on egg sac.
Mom still has dropsy. Total loss is 28 fry and probably the mom.
Would the furan have caused the early delivery and kill the fry.
Her sister developed dropsy when pregnant a few months ago and yes she came from the tank that is currently having a few problems with fungus and possible parasites.The guppy that has dropsy did not seem to have either fungus or parasites as she has been in the fry tank for a 6 weeks or so and that tank has been treated for parasites as a prophylactic with all the fry in there.
I have to look up what furan's affects on fry are. But pineconing can indicate organ failure and the fact that the mother was dying probably caused the early delivery and the early birth would have likely killed the fry in any case.
It is also reasonably likely that the infection that killed the mother started with her fry.
This type of death is not uncommon in livebearers. I think you acted correctly to try to save the mother even at the expense of undeveloped fry that usually die anyway.
Furan 2 is Furazolidone & Nitrofural. Both were once widely used in humans but aren't used in the US any more. Except Nitrofural is used topically on skin grafts on burned patients, Furazolidone can affect sperm and have other bad side effects but may cure whirling disease in fish.
Possible genetics could have affected her depending on how she was conceived idk much
but I'm almost positive that I have read that guppies sold at PETCO pet smart ixe. Look fine but then have internal diseases.