Help! i heard both of my sugar gliders fighting and i turned on my light and the dad had the dead baby in his mouth dead. should i separate them? what do i do?

Maybe the parents are new at this or maybe they knew something was wrong with the baby. I know it is hard, but not all survive. So sorry.

I am so sorry for your loss and your experience. I personally don't know a whole lot about those kinds of things, sadly one of the many reasons why I avoided having breeding gliders.

Did you just have the one Joey? How old are your breeding gliders? And how old was the Joey?

It's possible as suggested the Joey wasn't healthy, sad, but the glider way.

Personally, I recommend neutering male, and trying to keep them together.