A harness connector for securing a first tank to a second tank, for example for fastening an auxiliary air tank to a main air tank in scuba diving applications. The connector comprises a receiving member adapted to be secured to the first tank by a pair of tank clamps, and an attachment member adapted to be secured to the second tank by another pair of tank clamps. The receiving member and attachment member are formed so as to mate with one another, such as an attachment member with a T-shaped cross section mating with a receiving member with a U-shaped cross section. The harness connector further comprises locking means for selectively locking and unlocking the attachment member to and from the receiving member, such as a quick release type connector pin.