Barbara;689339 wrote: I think some are more likely to split than others. But I do think environmental stress can contribute. And then there are times they seem to split for no apparent reason.
Don't try to feed it until the mouth heals. You will know this b/c the recent split would have been through the mouth, resulting in the current clones having no mouth. Over the next 2 weeks you will see the mouth re-form from the outside, and slowly gravitate towards the center. When the mouth is back in the center, it is healed and ready to try feeding again (if you were feeding it in the first place).
Don't move or otherwise disrupt them until the mouths are re-formed and healed. At that time you could attempt to remove one to sell, or move to another tank, or you could choose to leave them both in the tank. They might not stay together, but generally I've heard success stories about keeping multiple 'nems in the same tank as long as they are clones of each other.
Good luck and have fun!