in your aquarium before it dropped fry? Did you gradually adjust it to the tank's water? Were there other fish in the tank? What were the ammonia and nitrite readings in the tank?
The first concern there is that a lot of us, when new to the hobby, see a very pregnant guppy and think of becoming guppy king or queen of our block - very rapidly. But moving such late term females can cause them to miscarry and/or internally hemorrhage.
A couple of people here have tried C-sections on recently dead females. I think PeterW was successful one time. One must more fast or the fry suffocate in the dead female.
The second concern is one about water quality. It is a rough process on both new aquarists and their fish, cycling a tank. Really pregnant guppies might have a harder time than males, fry and less pregnant females.
I'm really glad you put the fry in a hanging net and not in one of those plastic boxes.
That WWII model tug boat sounds neat. But is it designed for aquariums so that it doesn't leach (bleed) anything which might be unhealthy? And where can I get one? ;)
Next diagnosis please submit something like this as a diary. The software designers (not us) envisioned Logs as opuses or major essays on some aspect of the hobby, of several hundred or several thousand words or even tens of thousands of words. Because of voting the log take a lot longer to get to the everything page - whereas diaries are there immediately. :)