All my chicks have brooded in appliance boxes. I agree that a 10 gallon aquarium would be too small. Chicks grow really fast and need space for the food, water and to get away from the heat as needed. In the picture below you can see the box on the right with a piece of wire fence on top. The brooder light sits on top and the fence keeps the cats out. We put the chicks in a rubber maid bin or a small animal cage for "socialization" time.
