Leave them in the main tank until they breed, wait for the female start carrying, give her a week or two, then transfer her into the fry tank. Have the fry tank cycled and ready to go, then drain the water and add water from the main tank just before you transfer the female. As soon as she release the fry, remove the female. Return her to the main tank only after you have rescaped the main tank, so that all the fish have to reestablish their territories. Otherwise, she will probably be harrassed and killed when you transfer her back. Hope that helps.