How to clean my fish tank with babies in?

[JenlLouise]

I have recently bought 2 female guppies. We must have purchased a pregnant one as after just 3 weeks of having them, one of the females has given birth to lots of babies. I have read a few get eaten but due to having lots of plants and hiding places (and no other fish other than the mother and other female guppy), its now nearly 4 weeks on and all 23 babies have survived. They are about 1cm to 1.5cm big now and some have lovely colours coming already. I have spoken with an aquarium expert about sexing them in order to seperate the males to a different tank in order to hopefully prevent more breeding.
One issue though is how do I clean the tank? I know usually with tropical you just empty two thirds water and top back up with fresh (hope that's correct) but can I still do that with babies in? Also is there a way I can clean the gravel without having to take the fish out and empty it? I have had the water levels checked a couple of weeks ago and they are fine. Any help greatly appreciated.
Thank you

 

[Heather1]

Yes you can still change the water with babies in it. It will them grow actually. I have a vacuum for my aquarium to vacuum the rocks and get the waste out of them. I don't know that I would do that while the fry are still though. I haven't vacuumed up any fish yet, but babies are a little harder to see. Congrats on all of them surviving