I did a 25% water change with him still in the tank and he died that night. I was so upset to find him dead the next morning, especially since I think I should have removed him and re-accustomed him to the water. I did, however, notice that he was acting odd the day before, so I'm thinking the added stress might have done him in. I did the best I could for him with a fully cycled 10 gallon tank, but the problems began when the old filter broke and the tank went unfiltered for a day. That's when he started acting weird, but I thought he was just blowing a bubble nest in the still current.