The other fish will likely eat the fry if they are not removed. If you want to keep the fry the best thing would be to set up a small grow out tank so that they can get to be .5-1" before putting them back into the original tank. Live bearers have hundreds of fry throughout their life span so if you don't want to keep these then you'll surely have another chance at it. Fry requirements are the same as adults with the exception of needing smaller food and are more sensitive to toxins and ph/temp swings. Have a plan for what to do with the fry when they are adults though, many pet stores don't take in fish from customers and keeping them in a tight space while trying to find homes for them seems for some reason less humane to me than just letting them provide sustenance for your other fish.
