After a guppy has her fry, she is very hungry and this is why they eat thier fry if there is no other food available..
If she is in the trap btw and she dont drop within 48 hours, take her out of the trap cos it will stress her out to much, you will then have to keep a close eye on her...
If you do have to release due to her not dropping within the 48 hours.. look for her..
Dwelling on the bottom
Hanging around the top of the tank
Hovering near plants (or in them)
Hanging around the filter (if you have a internal one)
Hovering above the heater
Bear in mind that if she is doing any of the above, she will be almost static and not really swimming much.. usually this is when they are very near ready
ps, dont go by the gravid spot, im so sick of typing this.. the gravid spot can appear dark on females that aint pregnant, and appear light on heavy pregnant ones, all fish are diffrent and the gravid spot is so misleading.. the easiest way to tell is by the size of her belly (it will square off) or by watching for the above list i typed
Depending on the size of your fish and age.. she may not get big and still drop... also sometimes in the gravid spot you can see the babies eyes, this is a good indication she aint far off her drop (once again dont go by the gravid spots color as i said, light or dark, all are diffrent... , but if there is eyes, thats a good sign)
Hope this helped
When female guppy's give birth, they express a hormone which stops their appetite and helps prevent them from eating their own fry,
This is not actually true, they release the hormone to stop them from getting a appetite so that they dont eat to much and poo while giving birth, the anal passage opens and can press on the birth tube and can kill the fry as they are sqeezed through the remaining hole which she will struggle with so much, it also causes lots more problems as she becomes stressed..
