What on earth happened to it?

[Carmen]

Just a thought, but may have just been splitting?? Or starting to split and ....something went wrong? Here's a pic of mine starting to split and it split from center out looking like a hole was "blown" through it and you could see all the insides exposed. As far as the piece is concerned can you try to get it with a small net? Small pieces can survive but I would think it would need light and feeding.

Hope you can salvage the light guy. Sorry to hear.