how big do my fry have to be before they can be moved to my 35 gallon hex main tank with 2 black skirt tetras and other assorted fish i have swordtail fry and bubble molly fry how long before i can move them???
Assuming you don't want them eaten, bigger than adult mouths. If there are hiding places, they can be released earlier but there is no guarantee they will use the hiding places.
Personally I try and wait about 1 to 2 months before adding them. I like to be safe but i've added already in 2 weeks on extreme cases and they were okay but you just have to watch them like helterskelter said.