SISO Weekend Food is the simple, stress-free solution to automatically feeding tropical and goldfish for 2 to 6 days in your aquarium. Food units are dried and solid. The feeder, when placed in your aquarium, will dissolve and slowly release small particles of food. Solid food, which is slowly released into the water or when fish bite it. One unit feeds 10-12 medium sized fish in an aquarium. 10-15 gallon fish capacity., Will not block water In addition to feeding your fish, ingredients will help neutralize and purify aquarium water. Includes natural ingredients to meet the nutritional requirements of all aquarium fish Drop one unit into the aquarium and do not use it in an unfiltered or aerated aquarium or aquarium