A study by John Hargreaves and Semra Kucuk revealed that
brief exposure to NH3-N concentrations considerably higher
than the no-effect level (determined in toxicity tests run at constant
NH3-N concentration) did not affect the survival or
growth of three culture species: blue tilapia, channel catfish and
hybrid striped bass. Moreover, the concentration of total ammonia
nitrogen in ponds fluctuates over time, and higher concentrations
seldom persist for more than a few days.