High Ammonia Readings

for the week of 9/24/98

Though it’s not as commonplace as some people seem to think, sometimes an aquarium will show high ammonia levels when checked with a test kit. After ruling out the possibilities of New Tank Syndrome and False Ammonia Readings, it’s time to look into the possible causes of ammonia buildup as well as what to do about it.

High ammonia levels basically mean that, for one reason or another, the good (ammonia-eating) bacteria in your system are not keeping up with the amount of ammonia being produced. This, in turn, means that either too much ammonia is being produced or that something is inhibiting the bacteria from doing their job properly.

Ammonia is prouced as a major part of fish waste, and also when anything organic is allowed to decay in the aquarium. If a tank suddenly develops a high ammonia level, check for dead fish, plants, “live roc”” and uneaten food; generally speaking, it takes a very visible amount of any of these to have any impact on an ammonia reading. If a tank has either recurring or chronic ammonia problems, it is likely either overcrowded or overfed, and adjustments to stocking density or feeding habits need to be made.

Ammonia-eating bacteria are living things, and hence subject to trauma and death – which can usually be traced back to the actions of a well-meaning hobbyist. Too massive a water change can sometimes put a stop to ammonia breakdown, especially if the new water is not adequately dechlorinated or temperature-adjusted. Use – and overuse – of medications and antibiotics can also debilitate or kill the beneficial bacteria just as easily as the harmful ones. Changing of gravel or (at least theoretically) filter media might result in throwing away a significent number of bacteria. Finally, inadequate aeration may limit the bacteria’s ability to process waste.

After tracking down the likely causes, a partial water change (not too big, and make sure the new water is properly treated) will temporarily dilute the amount of ammonia in the water, and there are chemical additives that also help to remove or bind up what’s left. If all goes well, the ammonia-eating bacteria should kick back in after a few days

“Tip of the week” appeared regularly in 1999 and 2000.