when you see them swiming around the tank catch them if you can [ syphoning is the easiest way for me ..Jewels make pretty good parents , The male may start beating on his mate , If he does you should remove her [alive ] before it's to late . Keep an eye on them . In my experience , It's easier to remove the parents , they may even eat the fry . If you want them to breed , set them up in an almost bare tank [say a 20 long with a heater an air stone , better yet a sponge filter , an existing sponge could be of great service to you not only will it help to keep the water quality good but the fry may find something to eat on it ] , after the fry have hatched and become free swimmers take the parents out of the tank . Make sure you have something to feed the fry . Mine have taken prepared fry foods in the past , don't over do it with the food as you can easily polute the tank . Make sure their water is clean , change the water frequently 2[3] times a week , small water changes.