Now that spring is just around the corner it’s time to begin the loving task of opening up the pond. The transition of winter to spring can be tricky for the fish. Parasites and anaerobic (bad) bacteria thrive in cool waters before the fish have had time to build up their immunity. Aerobic (good nitrifying) bacteria take their time to establish in the biological filter so we run the risk of deadly ammonia and nitrite build-up in the pond during this time of year.