Does it grow near where you live in Turkey? Although a wetland product, is there any problem with it rotting in a fish tank and taking oxygen out of the water?

I fear that your goldfish will eat the baby guppies - perhaps before you even see them.

"If a fish can fit into the mouth of another it will." :(

That is not the fault of the goldfish - it is a natural behavior.

If your female guppy is laying on the tank bottom, is there a way to warm the tank gradually until it is a degree C warmer?

Goldfish are temperate zone fish. Yours would really be happiest in a cool container (maybe even in a bowl or pot on the floor - Chinese and Japanese fishkeepers sometimes keep them that way) and not in a tropically warm guppy tank.

To be a female guppy, by the way, usually is to be a pregnant guppy. ;)

One of the new acquisitions I set up tonight, is a fish from Turkey. Aphanius mento is just one of several Aphanius (sometime called Lebias) from Anatolia and regions to the east and south.

They are in separate tanks, but I'm just as excited to get them as some green snakeskin guppies.

Your experience of keeping guppies and other fish, leaving them because of the demands of school (and often beginning a career, starting a family and many other important, busy periods in one's life) and then returning to the hobby and craft of keeping aquaria is very common among the aquarists I've had the privilage of meeting.