Underwater photography is dangerous only if the diver is dangerous, and careless. Moving among wildlife above and below water is a skill that comes from practice. . . and observation about your behavior. . . what scares the wildlife, and what you do that doesn't scare wildlife. My beginnings as a diver was to shoot fish in competition, later I helped teach new divers, and couldn't take a speargun. I learned more about fish behavior when I could follow them.
The fish can "see" or detect a diver as far, or further away than you can detect them. Fish are not smart. . . but they are not stupid. Blow bubbles at a steady rhythm, avoid waving your hands, or your equipment within the comfort zone of the fish, and camoflage isn't necessary. Many years ago, a friend won a rigged contest and won a free wetsuit, bright orange! He was a 3 time national champion spearfisherman, and it was a joke knowing he wouldn't wear it during a contest. . . he wore the bright orange wetsuit, and continued to win contests. Fish could "see" the orange suit, but they didn't recognize orange as any greater threat than black.
Any fish, in any water, fresh or salt. . . can help you learn to swim with the fishes. Subtle movements that come from experience, and control of your equipment, and avoid any threatening swimming directly at fish, will be the teacher. Remember, your behavior is being judged by the fish, if you belong, they will ignore you. If any fish suddenly jumps or darts away, all the fish will become alarmed and avoid closeness with any other creature in the area.
