Abstract: An improved air delivering device for use in a fish raising pond is provided with a hollow shaft having a plurality of slantly drilled holes disposed thereon and connected to the output shaft of a motor. The motor is disposed on the roof of a shelter casing in which the output shaft in connection to the hollow shaft is housed. To the end of the hollow shaft is secured a sleeve having a plurality of discharge bores communicating with the hollow shaft and a blade assembly is integrally formed with the sleeve. An extensible air introducing duct in connection to the shelter casing permits air to be led into the shelter casing for mixing with water in the hollow shaft and discharged through the multiple bores into the underwater area so as to increase the oxygen content level therein.