An aquarium with a flexible side wall includes a support arrangement. The support arrangement can include a lower support that serves as a base and an upper support capturing an upper edge of the flexible side wall to distribute forces applied to the upper edge of flexible side wall so that a force applied to a discrete location to the side wall is distributed across a relatively larger portion of the side wall than at the discrete location for preventing localized buckling of the side wall preventing spilling. The support arrangement includes an upper support formed of a ring and a ring-shaped insert received in a cavity of the ring providing opposing support surfaces engaging an upper portion of the flexible side wall. In a preferred embodiment, the ring and ring-shaped insert nest to clamp part of the side wall therebetween.
