Traditionally, swimbladders of fish have been modeled in two regions. In the acoustic long wavelength region, i.e., λ much larger than the dimensions of the swimbladder, the gas‐filled bubble has been used. Since a spherical bubble has a very sharp resonance, damping terms have been included to broaden the resonance peak. The spherical bubble has been stretched into a prolate spheroid without reformulating the bubble theory [M. Strasberg, L Acoust. Soc. Am.25, 536‐537 (1953) and R. H. Love, J. Acoust. Soc. Am.64, 571‐580 (1978)]. At short wavelengths compared to the dimensions of the swimbladder, the scattering process depends on the shape of the swimbladder. Experimental and theoretical studies of the sound scattered by swimbladders include measurements of fish and numerical integrations of the Kirchhoff diffraction integral. The Kirchhoff approximations give “good” approximations to the backscattering cross sections at short wavelengths [K. G. Foote, J. Acoust. Soc. Am.78, 688‐700 (1985) and M. A. Do and A.M. Surti, J. Acoust. Soc. Am.87, 1588‐1596 (1990)]. For a single model, a finite gas‐filled cylinder can be used over the whole frequency range. Stanton's approximation for the finite fluid cylinder was used and the fluid used was a gas [T. S. Stanton, J. Acoust. Soc. Am.83, 55‐63 (1988)]. It will be shown that the gas‐filled cylinder model fits a well‐documented set of data [D. V. Holliday, J. Acoust. Soc. Am.51, 1322‐1332 (1972)]. [Work supported by ONR.]