The invention relates to a novel energy-saving fish tank. The novel energy-saving fish tank has the advantages that through design of a filter device and by the adoption of the centrifugal sedimentation principle, fish feces and impurities in water can be effectively cleaned prior to be discharged in a concentrated manner, and cleaning effect is achieved to the greatest extent under the situation that normal water circulation is unaffected; in addition, water cleaning effect can be improved by arranging the filter device on the fish tank, the fish tank can be automatically oxygenized and the impurities at the bottom of the fish tank can be cleaned by the design combining a water supply channel and a drainage channel, the fish tank can be cleaned thoroughly, adding of a feeding device and a bottom dirt blowing device is not needed, manufacturing and maintaining cost of the fish tank is lowered, cleaning at regular intervals is not needed for a user, maintenance burden of the user is avoided, multi-level water purification is achieved, appreciation effect is improved, and living environment of fishes is optimized.