Fish disease is difficult to cure, because the sick fish is very weak, and if drugs are not used properly, fish disease will be more serious. Fish diseases are mainly caused by long-term poor water quality. Clear water does not mean that there is no ammonia toxicity in water. The key to raising fish well is filtration, that is, filtering fish feces. Toxins in water are all produced by fish feces. Only by removing ammonia from fish feces can we maintain the stability of water, which is more suitable for fish to survive, and fish can be healthy and less sick. If the filtration effect is not good, the ammonia content in the water will be high, and the fish will gradually weaken and be vulnerable to the attack of viruses in the water if they live in the water with ammonia poisoning for a long time. Some hazards are not manifested at once, but have a process of accumulation, generally starting from fish with weak constitution. Baidu Yongqing filter, this filter system has the function of automatically cleaning fish manure, which will be helpful.