my guppy and platy fry are between 1 month and 2 months. The water in the tank is completely green. I'd like to do a 100% water change - 80% didn't cut it a few weeks ago. they won't die will they?
I would do a normal 30% water change and see too it that you are not keeping the lights on for more than 10-12 hours a day. Sounds like an algea bloom.