The present invention relates to a live fish tank water purification apparatus for a live fish tank. The live fish tank water purification apparatus flows live fish tank water through a sterilization discharge chamber with UV lamps from an aeration chamber with an air bubble diffuser arranged therein in order to preliminarily remove the contaminants in the live fish tank water in the form of floating bubbles and execute the final sterilization treatment operation with UV rays. More specifically, a water temperature adjusting chamber having a built-in water temperature adjuster and a deaerating chamber for blocking air bubbles are individually arranged on the upper and lower parts of the front surface of the aeration chamber. A discharging port for discharging the live fish tank water from the water temperature adjusting chamber is arranged below a bubble chamber on the upper end of the aeration chamber collecting the floating bubbles. A bubble blocking chamber is tilted in a downward direction and toward the floor surface of the deaerating chamber from the inner lower part of the aeration chamber while the deaerating chamber is fully connected to the lower space of the aeration chamber. Partition plates for partitioning the aeration chamber and the sterilization discharge chamber can be installed as a transparent acrylic plate in order to prevent freezing of the floating bubbles by discharging the live fish tank water heated at a predetermined temperature to the part right below the bubble chamber during winter as well as preventing malodor and spoilage of the floating bubbles by discharging the live fish tank water cooled to a predetermined temperature to the part right below the bubble chamber during summer. The bubble blocking plate is used to fundamentally prevent the bubbles in the aeration chamber from flowing into the sterilization discharge chamber with contaminants. The UV lamps emit UV rays to the aeration chamber through the transparent acrylic plate in o
