The Api 7-day Pyramid fish feeder is suitable for both coldwater and tropical fish and contains real food that automatically feeds your fish when you are on holiday. Feautures: Contains real food pellets to nourish your fish Pack contains 4 pyramids which will each feed up to 20 average size fish for 3 to 4 days To use simply place the pyramid fish feeder in your aquarium. It will immediately start to dissolve, giving off a stream of fine bubbles. Within a few hours the first nourishing food pellets will begin to swell and push out of the pyramid. Not to be used in goldfish bowl or aquariums without adequate filtration.