Disclosed is an inflatable container suitable for use as a portable aquarium. The inflatable container has an upper open end and side walls which are easily and economically constructed from a single sheet of flexible film material. The sheet is folded upon itself into substantially two overlapping half sections with portions of each half section being sealed together to form four side panels. The remaining portions of the overlapping half sections form an inflatable tubular, flexible framework including an upper and a lower tubular rim and at least four upstanding tubular columns which surround the side panels. The tubular framework and side panels are formed with only two sealed seams joining the longitudinal and lateral edges of the film sheet, one of which extends longitudinally along the surface of the lower tubular rim and the other of which extends laterally along the surface of one of the upstanding tubular columns. The upper tubular rim of the framework surrounds the upper open end of the container and is essentially seamless except for a portion of the lateral seam extending along the surface of the upstanding tubular column. A bottom panel is joined to the lower tubular rim and valve means are mounted in the framework for inflating the container.