Ever seen "Finding Nemo?" Maybe your fish was trying to sabotage the filter system for his great escape plan.
:hilarious
P.S. Also, I have a cleaner shrimp. I didn't do the drip acclimation, but I did do the thing where I added a quarter cup of water every ten minutes until the bad was full, dump out half the water, do it again, then add him to the tank. He's been doing great. He cleans all my fish except the Scooter Blenny, plus he eats the Seaweed Salad I put in the tank, and he scampers around and gets the fish food that falls on the bottom of the tank. He'll go all over your hand if you put it in the tank. I'm actually considering getting another one because I like him so much. I have to read up and see if two will live together. I didn't know about the drip method until after I got him, by the way.