Hi! I had a 2" crowntail betta named Chizuru; after I cleaned his tank before I went to my lab today he looked a bit sluggish and sat at the bottom of the tank. I went to class as he usually did this after I cleaned his tank so I thought nothing of it (he was an odd fish), and when I came back 3 hours later he was dead where I left him. He had gone from a vibrant indigo color to a pale blue with his fins turned white? He was a very healthy fish and his tank was always between 76-80 degrees (silly thermometer is hard to read). I have had him since January in an established tank. Does anyone have any ideas what might have happened? I used a tank cleansing tablet by Jungle called "Bowl Buddies". I used those the whole time I had him. Plus my friends in sympathy bought me a new crowntail, but should I wait to put him in the tank? I bought some Tetra Aquasafe at Wal-mart and put a 3 drops in the tank 10 minutes ago.(although I had forgotten to shake the bottle) I would hate to leave my new boy in that stupid little cup though, but should I let the tank sit for a few days? Thanks in advance!!