What fish tank's measure 30 inches wide?

Do you mean 30 inches long? Don't know of any tanks 30 inches wide. 3 tanks come to mind that are 30 inches long, these are outside dimensions. Length, width, and height (inches) 20 gallon long 30 1/4 x 12 1/2 x 12 3/4 29 gallon 30 1/4 x 12 1/2 x 18 3/4 37 gallon 30 1/4 x 12 1/2 x 22 3/4