If ever in Quincy, MA I will make sure I am on my best behavior so as not to accidently upset you 8O .
Seriously, sorry for your loss, but you might want to do a little more detective work. First of all a 15 gal
is a little small for SW
and water levels are tougher to maintain. In the interest of your other inhabitants you might want to check your levels.
I just added a CBS to my 75gal well stocked(politically correct for overstocked) setup this past week. As soon as I read your post I closely inspected and all inhabitants were still present. Before adding the CBS I did my homework including checking here and everyone advise me that a CBS is a pretty compatible tank mate.
I fear you may have punished the CBS for its natural behavior. I would not add anything else to your setup until you verify all is currently well. How many fish do you have anyway?
Best of luck,