Fireplace an interesting place for fish tank?

I would just make sure the chimney isn't drafty and isn't going to get the tank & water dirty. I live in a very dry climate so I wouldn't know about this but I wonder if condensation would form in such a closed space in a more humid client. A heater and air stone are standard equipment for a warm water tank but would be a must for this setup. For cleaning and maintenance, make sure you have some way to easily pull the tank out of the fireplace.