This image shows one of the underwater performers that entertained visitors to the Aquarena Springs theme park during the middle of the 20th century. Dressed as a clown, the swimmer is able to breathe through the use of the air tube held in the mouth.

A Natural Color Card by W. M. Cline Co., Chattanooga, Tennessee
The description states:
AQUARENA, SAN MARCOS, TEXAS
GLURPO AQUARENA’S FAMOUS AQUATIC CLOWN, who performs his acts under-water. Thrilling under-water shows are presented by the world’s only submarine theatre at this attraction every day of the year (except Christmas Day).
–The underwater theater is closed now that the Springs are a conservation area. This card was used and is dated 3 July 1962.