PROBLEM TO BE SOLVED: To provide a device and a method for feeding aquarium fish while improving both a feeding efficiency without sparing the feed and a prevention of the pollution of the water in a water bath.SOLUTION: An aquarium fish feeding device for feeding aquarium fish 11 kept in a water bath 10 comprises: a cylinder 2 having a side wall arranged with inflow small holes 21 and 22; and a metallic feeder 3 disposed at the lower end of the cylinder 2 and made diametrically smaller downward to have a feeding small hole 33 at its lower end crest. The water to flow inward from the feeding small hole is made to flow out through the feeding small hole establishes a convection to drop the food for the aquarium fish into the lower end top of the cylinder by making use of a convection established by flowing down the water through the feeding small hole.【課題】観賞魚に餌を給餌する上で、餌を無駄にすることなく給餌効率を向上させ、また給餌時に水槽内の水の汚濁を防ぐ。【解決手段】水槽10内で飼育する観賞魚11に給餌するための観賞魚用給餌器において、側壁に流入用小孔21、22が配設された筒体2と、筒体2の下端に設けられ、下方に向かうにつれて縮径化されてその下端頂部に給餌用小孔33が形成されてなる金属製の給餌体3とを備え、記流入用小孔から流入する水が上記給餌用小孔を介して流出させることにより生じる対流を利用して観賞魚用餌を上記筒体の下端頂部へ落とし込ませる。【選択図】図1