PREVENTION AGENT FOR FISH AND PREVENTIVE TREATMENT OF FISH

PURPOSE: To obtain a preventive for fishes containing a low molecular alkali metal humate and useful for prevention of disease caused by fungus. CONSTITUTION: This preventive includes a low molecular alkali metal humate and is added to the water surrounding fishes to heighten the resisting power of fishes bearing stress and consequently the survival rate thereof and further reduces infection of disease caused by fungus. The concentration of the preventive added to the water surrounding the fishes is in the range of 0.5-10ppm according to the water hardness and 0.8-2ppm concentration is sufficient in a case of soft water or deionized water. The preventive is preferably added successively every 3-5 days. The fishes bearing stress, for example after transportation, become active and manifest a luster peculiar to healthy fishes and the survival rate is extremely improved, when the fishes are added to the water containing the low molecular alkali metal humate.