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Ammonia In Ponds and Aquariums – The Invisible Killer

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Ammonia In Ponds and Aquariums

The Invisible Killer

Ammonia in ponds and aquariums is a fairly common problem. Ammonia stress and poisoning is often the number one cause of fish illness and deaths when setting up new aquariums, small ponds and quarantine tanks. This is often referred to as ‘New Tank Syndrome’. It is not usually as common a problem in new larger ponds because the ammonia is diluted in the larger volume of water and doesn’t reach toxic levels. Ammonia stress can also occur in well established ponds for a variety of different reasons. A short lived ammonia spike is not likely going to kill fish, it can stress and weaken fish enough to make them vulnerable a parasite or bacterial outbreak. 

Luckily, koi and goldfish as well as many aquarium fish are quite resilient and can withstand low ammonia levels for a few days without any adverse effects. But ammonia levels can rise to dangerous levels quite quickly and lead to serious fish health problems and deaths.

What is Ammonia and Where Does it Come From?

Ammonia is the primary waste product of fish. It is excreted through their gills and as urine. It can also come from decaying plant matter, such as tree leaves that get into the pond in the autumn. As well as dead and decaying algae, dead fish or other animals in the pond.

What are the Symptoms of Ammonia Stress?

The first signs of ammonia stress are often associated with the behavior of the koi or goldfish. In ponds or aquariums with high ammonia levels, fish will often become less active and hang gasping at the surface. Fish will often also congregate at the base of  a waterfall, stream or filter returns where there is a current.

Other signs include:

  • sitting on the bottom
  • loss of appetite
  • fins clamped close to their body
  • excess mucous slime coat

Read the rest of the article in our Ammonia In Ponds and Aquariums and How to Lower It page

About the author

Graduated from the University of Guelph with a B.Sc. (Hons) Marine Biology. With over 30 years experience in the aquarium / pond industry, his passion for fish includes ponds, marine aquariums and water features of all sizes. Previous work includes Ripley’s Aquarium, the Toronto Zoo, Bass Pro Shops, Rainforest Cafe and the National Museum of Kenya.