When was the first successful underwater photograph of a fish taken?

Underwater photography developed gradually, and some of the earliest successful images of fish and other marine life were made in the 1920s and 1930s as waterproof housings and flash systems improved. A well-known pioneer was William Longley, who worked with National Geographic and helped produce striking underwater color images in the 1930s. These advances transformed marine science and public understanding of sea life. Before this, photographing fish underwater was extremely difficult because of light loss and equipment limits.