To provide a simple air-cum-water pump for an appreciation fish water tank at a low cost in which a noise at the time of feeding water is small and a good quiet sense can be ensured and to provide an appreciation fish water tank device with a migration passage in which a noise at the time of feeding water is small, a starting work at the time of an operation beginning is outstandingly simple and a water circulation in the migration passage is good.

In the pump, a feeding out port 64 and an introducing port 63 are provided on the outside of a casing 5 and a passage arriving from the introducing port 63 to the feeding out port 64 through the inside of the diaphragm 4 is made to a closing system circuit. A plurality of suction valves and discharge valves are preferably arranged against one diaphragm. The pump is used as a water sucking/discharging device for an appreciation fish water tank with a migration passage and the introducing port of the pump is communicated and connected to the suction port provided at an upper position of the migration water tank.