I have a bta that split and was going to give the second one to my friend. For some reason the second one has disappeared? Could the other bta have swallowed him? That's the only logical explanation I've come up with.
No, it probably moved behind/under a rock, or it has deflated for a day or so.
It should reappear soon. A clone BTA will not eat its sister IME and I've had 5-6 clones.
I don't know if an anemone could eat another anemone--I would highly doubt it.
Different species of anemones in the same tank can start a chemical war to inhibit each other.
If it split from tank stress it will usually dissolve and breakdown never to be seen again. If it split from flourishing conditions they usually reappear once they are happy in their new position. . a day or two. I have experienced both in my tank. I currently have an anemone that has split twice and now all three are HUGE. I think they may split again soon due to their rapid size increase. Hope it all works out for ya! Let us know.