This isn't usually a big issue. Many people have Festae and other cichlid pairs from the same spawn that go on to produce healthy fry. The problems generally come when it has been done over multiple generations. But introducing new lines when ever possible is always best. I know that some people will either growout two groups from different parents or introduce fish from another source later on. When dealing with picky Festae, you don't always have much to say about who they choose to pair with. They can be downright ruthless when selecting mates and when upset with their long-time mate.Not really too sure, but I don't think you would want a pair out of them because they are from the same source and could potentially be from the same spawn, which could be genetic issues if they were to produce spawn.