Floating plants (not Anubias) are very important to female "Livebearers", like your Guppies and to their fry. I keep several tanks and all have areas with thick floating stem plants. Anacharis is a fast grower and makes good hiding places where the pregnant females can feel separated and more comfortable. The fry when born, will swim to the top of the tank for a breath and go to an area on the surface that's heavily grown, for protection.
If you've already got such a tank, then no problem. If not, then you need to get some floating plants if you want a high fry survival number.
"Fear not, my young apprentice. Just change the tank water."