Marine fish that are subject to fresh water basically there cell structure explodes. Same vice cersa. Sometimes when trying to save a fish that is infected with some type of parasite this procedure will be used. If done when the fish is to far gone, of incorrectly yes it will kill the fish. But I agree the chlorine probably had alot to do with it. I have also been there, and the chlorine levels at that slide are probably the max allowed. Just like the sign at my pool in the back yard says. Notice the is no P in our OOL please keep it that way. But all jokes aside it was a tragedy, 2 fold, that it happened, and that the shark was there in the first place.