My ex took my daughter over the weekend then on Sunday decided he wasn't returning her. Claiming I am an unfit mother over a few bruises on leg that neither myself or her step dad noticed nor inflicted. We had a decent arrangement but no notarized signed paperwork. I was trying to keep child out of courts. What are the factors to be determined an unfit mother and what does my ex have to prove to get my daughter taken away from me?

The only one, that is being hurt by not going to court is the child.

What is needed, is to convince the judge, and/or they will give joint custody.

So you hire an attorney, file in court for child custody and child support

Without a legal custody order in place, your ex has as much right to the child as you do. Depending on the location and shape of the bruises, a doctor can sometimes determine how the occurred after an exam and interview of the child. You might want to get an attorney.