The invention discloses a method for culturing ricefield eels in a water tank and relates to the field of aquaculture. A stainless steel water tank of which the upper end is provided with an opening serves as a culture pond for the ricefield eels; a desected bamboo pipe is arranged at the bottom in the water tank; one third space of the bamboo pipe is filled with fallen leaves; the lower end of the side wall of the water tank is provided with a drain pipe; eclipta prostrate, acalypha australis, ampullaria gigas and water spinach are put into the water tank; after water is added into the water tank and fries of the ricefield eels are put into the water tank, the water spinach is harvested periodically; the water added into the water tank is subjected to treatment by a traditional Chinese medicine composition, and the treatment method comprises the following steps of wrapping the traditional Chinese medicine composition by using gauze, soaking in water for more than two hours, and taking out. According to the method, culture conditions are convenient to control, the method is not limited by geographical conditions, the development of the ricefield eel aquaculture can be promoted in a wider range, space is saved, industrial aquaculture can be realized, and after the water is treated by the traditional Chinese medicine composition, the parasite infection rate of the ricefield eels can be reduced by 40-60 percent.