IME, julies care for them initially, but then the fry venture out of the cave and off into the world as they get older. In a species only setup, this isn't so bad because the parents will become aggressive towards the older fry in time if they are raising more and push them off. In the community tank as you've seen, non-julies may eat them. I wouldn't be surprised if you still have a few that have found crevices to hang out in and are there, despite them all appearing gone at this time.