Treatment for high TAN concentrations is difficult in large pond culture systems. Pumping fresh water into the pond is not a practical or economical means of reducing the ammonia level for the whole pond. It does, however, provide a small area near the inflowing water where fish can go to find somerelief Maintaining high dissolved oxygen levels by aeration will slightly reduce the toxic effect of un-ionized ammonia. In addition, TAN levels may be reduced through increased aerobic bacterial activity due to higher oxygen levels. Temporary reduction of feeding rates is recommended until TAN levels decrease to an acceptable level.