I once made the mistake of putting hot water in my tank as a water change. I was new and it felt ok, kinda like a nice bath. Then I check the thermometer, and its in the 90's. I put one scoop of ice from the freezer in the tank and just replace the melted ones for about an hour. The fact that the hot water just hit them from the water change ment that that was what they didn't like. So, I see all of my fish swimming within two inches of my ice cubes. It kinda looked like the Titantic without the sad ending. Luckily, none of my fish died, but then again they were African Cichlids. Now, I check the temp with an extra thermometer I have around from an old tank. Learn the leason and move on. What is it they say? Life's a hard teacher?