In China, especially on trains between Shanghai and Hong Kong, I saw solar panels installed above ponds. I never managed to find out for sure what I was seeing, but I suspect I was looking at fish farms.
In which case, the solar panels would have been reducing the amount of sun hitting the water. Keeping them cooler, and reducing the energy for algal growth, which can feed on poo from the fish and make them sick.
(2/2)