Why do few or no Olympic swimmers get fungal toe nails?

Athletes who compete at that level usually have the benefit of high-quality facilities that stress proper sanitation.

In addition they also enjoy high level support and regular check ups by physicians, coaches and trainers.  Competitive swimmers tend to pay a lot of attention to grooming (even the swimmers in my high school shaved all their body hair before a big meet).  I wouldn't be surprised if Olympic swimmers from the top nations also got regular manicures and pedicures as part of their training.

Is it all that chloride?