If you really want the fry to live, then seperating the fry to another tank would be a good choice. But it's your call, if you leave the fry with the parents it's just a matter of whether you have a good, responsible, and caring pair that won't eat your fry. And from the looks of it, you've got a very good pair. If I were you I'd buy another 10 gallon and a sponge filter or two. That shouldn't cost more than 20$, but only if you want to raise all of your angel fry to a resonable size to eventually sell them to your lfs for a little store credit. That's just IMO.