Angels are notorious for moving their fry around. It's a natural protection manuver. As long as the fry are not free swimming yet, they are all in the same general area. If you can isolate the area where you last saw the fry from the rest of the tank, once they become free swimming, use a smaller siphon hose (I use 1/2" diameter clear plastic vinyl tubing) and slowly siphon the fry and the water into the 10
gal tank. Start off by using all the water from the breeding tank then do partial water changes so as to not shock the fry from the move. Use a sponge filter only for best results with the fry. Once free swimming, the fry will do best on newly hatched baby brine shrimp for food. By keeping them in a bare 10
gal, you'll be able to see what food doesn't get eaten and can siphon it out of the tank to prevent pollution.
Be aware that if you have a normal spawn of about 100 fry, you will need to move them into a larger grow out tank in about 30 days. A 10
gal is not a good grow out tank for Angels.
If you have any other questions, feel free to PM me. Good luck with your new fry