Supersaturaton of DO is caused by excessive planktonic algae and some factor that causes the excess DO to remain in the water. Typcially, as the DO concentration reaches above 120-150% it diffuses into the atmosphere. Obviously your pond conditions allowed the DO to continue to accumulate. At supersaturation oxygen bubbles accumulate on the fish gills and eventually causes death as the condition progresses.
Last edited by Bill Cody; 09/08/16 11:00 AM.
