The insurance fraud
I can understand why the aquarium owner sabotaged the tank for the insurance, and he would have gotten away with it, if it wasn't for that meddling kid. But to try to attack the rescuers and kill willy after the rescue began is dumb. How is he going to explain that to the insurance company. He might as well turn himself in for insurance fraud. Now, not only is he not going to get his million dollars, but he is going to jail as well. He could have just sat back and said, "hey, ok, I failed, but its still my word against the kid that it was just an accidental leak in the tank."
Just my thoughts on the subject.