Ammonia Poisoning

Definition: Ammonia (NH₃) is a highly toxic nitrogen compound that forms in aquariums from fish waste, uneaten food, and decomposing organic matter. Even small amounts can be deadly to aquatic life.

How do I test for ammonia levels?

Use a reliable liquid test kit designed for freshwater or saltwater aquariums. Test weekly, especially in new setups or after adding fish. Safe levels should read 0 ppm.

API Master Test Kit
What are the signs of ammonia poisoning in fish?

Gasping at the surface
Red or inflamed gills
Lethargy
Loss of appetite
Erratic Swimming

What causes ammonia spikes?

Overfeeding
Overstocking your tank
Inadequate Filtration
Lack of beneficial bacteria
Dead fish or decaying plant

How do I lower high ammonia levels quickly?

Perform an immediate 25-50% water change
Add a water conditioner that detoxifies ammonia (Like Seachem Prime)
Stop feeding temporarily
Ensure your filter is working
Add beneficial bacteria supplements to help jumpstart the nitrogen cycle

Is ammonia ever safe at low levels?

No. Any detectable level of free ammonia (NH₃) is unsafe. Ammonium (NH₄⁺) may appear in low-pH tanks and is less toxic, but it still indicates a problem in water quality.

How does ammonia fit into the nitrogen cycle?

Ammonia is the first stage of the nitrogen cycle. Beneficial bacteria convert it into nitrites (NO₂⁻) and then into nitrates (NO₃⁻), which are less harmful. A fully cycled tank should have 0 ppm ammonia and nitrites, and low nitrates