How to Lower, Remove and Get Rid of Ammonia in a Fish Tank

Ammonia is extremely harsh and will kill your fish. Whenever you discover a rise in the level of ammonia in your aquarium, ensure you work to reduce it sufficiently.

Ammonia (NH3), is a highly toxic, invisible chemical that accumulates in the system of your fish. Unfortunately, it is produced naturally in every aquarium. When organic waste in an aquarium begins to break down, it forms ammonia. The organic waste is produced by

  • Decaying algae
  • Dead pieces of plants
  • Uneaten fish food
  • Fish breathing
  • Waste from fish (excrete)

How Can You Lower Ammonia in Aquarium 

Some of the ways used to lower ammonia in an aquarium include:

  1. Partial Water Change 

An ammonia spike in your aquarium can be dealt with quickly and effectively with a 30 percent water change. In some cases, you may need to perform a whole 50 percent partial change if there is too much ammonia.

Carrying out a partial water change

  • Use a new bucket free of any chemicals or soap traces. Preferably keep it only for aquarium maintenance. Start by placing normal tap water into the new bucket and proceed to dechlorinate it. Allow it to sit overnight in the bucket,
  • Alternatively, you can use a dechlorinating agent which is easily available at a pet shop near you.
  • After dechlorinating the water, turn off all electricity to the fish tank including the filter and light.
  • Remove between 30-50 percent of the water from your aquarium by siphoning it out with a hose.
  • Slowly pour the dechlorinated freshwater into the bucket into the fish tank.
  1. Cycle your Aquarium 

New tanks have very few beneficial bacteria in them but the beneficial bacteria are vital for any fish tank because they help reduce the ammonia in the water. So, consider increasing the beneficial bacteria in your aquarium by introducing an ammonia source, which will jump-start the process of converting it into nitrite, which in turn is converted to nitrate.

  1. Improve Filtration 

Ammonia levels in the aquarium can spike as a result of weak filtration. Filtration can be improved by undertaking the following steps.

  • Use filter 

In case you have not been utilizing a filter, it’s time to introduce one. Other than keeping the water clean, a filter also provides a conducive space for the beneficial bacteria to grow. That in turn aids in reducing the ammonia levels in the tank. For a small sized tank of about 20-gallons, a filter that you can hang on its back will suffice. But a higher capacity tank needs to use a canister filter.

  • Introduce another Filter 

You can add another filter to the existing one on your aquarium to improve its filtration. If you are utilizing a canister filter on a large aquarium you can also add on a hang on the back filter for better service.

  • Clean out the Filter 

If the water doesn’t flow freely through the filter, then it means the filter is clogged. Lots of caution needs to be exercised while cleaning the filter because it is home to most of the beneficial bacteria in the aquarium. If done haphazardly it can result in the loss of all the good bacteria in the filter. It is advisable to clean the filter using aquarium water to preserve the beneficial bacteria.

  • Get rid of Unnecessary Impurities 

Impurities like food leftovers, dead fish and plants, fish waste, and decaying algae cause an ammonia spike in the aquarium. Such impurities should be removed from the water using a simple fishnet. Lots of food leftovers in the aquarium is an indication that you are overfeeding your fish and you need to reduce the amount of food you give the fish.

  1. Vacuum the Substrate 

Regular cleaning of the substrate by siphoning will eliminate the impurities trapped in the substrate in your aquarium. If left unchecked these impurities can cause an increase in ammonia levels.

  1. Increase Aeration 

Aeration of the tank lowers ammonia levels by expelling ammonia gas into the air. The dissolved ammonia gas is forced out of the water and it enters the atmosphere through aeration. When aerating the tank ensure that it is not covered with a lid. Aeration can be done with an air pump, back hanging filter, or spray bar.

  1. Upgrade The Tank 

Overcrowding can cause a spike in ammonia levels. Lots of fish in a cramped space produce too much waste that increase ammonia. As the waste in the water increases, the ammonia levels will shoot up. This can be addressed using a bigger tank with a lot more water that can help mitigate the ammonia, hence reducing the levels.

  1. Live Plants in the Aquarium

Keeping plants like Anubias, Java fern and Java moss in the tank is an effective way of reducing ammonia. They can get micro and macronutrients from food leftovers in the aquarium and waste produced by fish. Uneaten food and fish waste act as fertilizer for live plants, which spurs their growth. In turn, plants produce oxygen, which is beneficial for aquatic life.

  1. Increase Beneficial Bacteria 

To increase beneficial bacteria consider adding gravel from an established aquarium. Good bacteria are known to reside in gravel. Also, filter pads from an existing fish tank can have the same effect. The filter pad or gravel can be sourced from other fish owners or pet shops.

  1. Preserve the beneficial bacteria 

Beneficial bacteria reside in gravel and the filter of the fish tank. When you maintain your substrate and filter using regular tap water, you risk losing all the good bacteria The best practice is to use aquarium water to clean to preserve the beneficial bacteria.

  1. Try Neutralizing Drops 

Neutralizing drops make ammonia harmless but do not remove it from the aquarium. Biological filtration is necessary to get rid of it.


Ammonia levels can rise rapidly, before undertaking a permanent solution. It is prudent to do a partial water change or use neutralizing drops in the interim. Monitor ammonia levels in your aquarium regularly to avoid losing your fish to ammonia poisoning.