High levels of total ammonia nitrogen as NH4+ are stressful and harmful to the growth of Nile tilapia juveniles - doi: 10.4025/actascibiolsci.v35i4.17291. Acta Sci. Biol. Sci. 2013;35(4):475-481. doi:10.4025/actascibiolsci.v35i4.17291