With high irradiation intensity stability, sterilization efficiency of DECO UV sterilizer can reach 99% and sterilization service life can be about 9000 hours long. After UV irradiation, the structure of DNA and RNA of bacterium, viruses and algae microorganisms in water can be damaged. As a result, the cells cannot regenerate and reproduce until death. Thus achieve the purpose of water sterilization and purification to greatly reduce the probability of fish disease. The shell is made of PVC or stainless steel.