A:Answer Hi David, thank you for reaching out here! The weight capacity of this stand is 200 LBS. Depending on the starting weight of your fish tank, and knowing that 1 Gallon = 8.34 LBS, you should be able to calculate how big of a fish tank you can handle (glancing at a quick Google search, it seems that you should be able to support fish tanks at about 20 or so Gallons or less?). Thank you!