What Makes Ammonia Spike in the Pond?
By Dr. Wiphada Mitbumrung, Ph.D. Applied Marine Biosciences — Wed Jul 22 2026
Ammonia spike is one of the most common water quality problems in shrimp ponds. It usually happens when the rate of ammonia production is higher than the rate of ammonia removal. Ammonia is continuously produced from uneaten feed, shrimp feces, dead plankton, organic sludge, and decomposition of nitrogen-containing organic matter. Under normal pond conditions, this ammonia should be converted through the nitrification process.
In a balanced nitrogen cycle, nitrifying bacteria convert ammonia into nitrite, and then nitrite into nitrate. This process is mainly carried out by autotrophic nitrifying bacteria. However, nitrifying bacteria grow slowly and are sensitive to environmental changes. When the pond has high organic loading, low oxygen, unstable pH, low alkalinity, poor mineral balance, or weak bacterial establishment, nitrification cannot keep up with ammonia production. As a result, ammonia starts to accumulate in the water.
The problem becomes more serious after phytoplankton crash, overfeeding, heavy rain, sudden pH change, or rapid increase in biomass. These conditions can increase organic decomposition and release more ammonia into the pond. At the same time, nitrifying bacteria may become less active due to poor oxygen availability, low alkalinity, or unstable water chemistry. This creates an imbalance in nitrification, where ammonia production continues but biological conversion becomes too slow.
To prevent ammonia spike, pond management should focus on supporting the growth and activity of nitrifying bacteria. Nitrifying bacteria need a stable environment, sufficient oxygen, essential minerals, and suitable alkalinity to function properly. Essential minerals support bacterial growth, enzyme activity, cell function, and biological metabolism. Without enough minerals, nitrifying bacteria may not establish or perform efficiently even when ammonia is available as a substrate.
Alkalinity is also very important because nitrifying bacteria are autotrophic bacteria. They use inorganic carbon, mainly bicarbonate and carbonate, as a carbon source for growth. During nitrification, alkalinity is consumed, so low alkalinity can slow down ammonia and nitrite conversion. When alkalinity drops, pH becomes less stable and nitrifying bacteria become less efficient. This can cause ammonia to remain in the pond longer and increase the risk of toxicity.
Therefore, ammonia spike is not only caused by high waste production. It is mainly a sign that the nitrification system is imbalanced. Effective management should reduce organic loading, maintain good dissolved oxygen, stabilize pH, supply sufficient alkalinity, and provide essential minerals that support nitrifying bacterial growth and biological function. When nitrifying bacteria are active and well supported, ammonia can be converted more efficiently and the pond nitrogen cycle becomes more stable.
