How much would a 200 gallon fish tank weigh empty?

An empty 200 gallon rectangular fish tank made of glass will weigh approximately 150 pounds (68 kilograms).

This estimation is based on the assumption that the tank is made of standard 1/4-inch (6 mm) thick glass. The weight may vary depending on the actual dimensions of the tank, the type of glass used, and the presence of any additional features such as a frame or lid.