How to Safely Lower Ammonia Levels in Your Aquarium

Ammonia is extremely harmful to fish and other aquatic creatures. The safe level of ammonia in water is 0 parts per million (ppm). If it reaches just 2 ppm, it can lead to the death of fish in your aquarium. By evaluating the water quality and making necessary adjustments, you can bring ammonia levels down to a safe range suitable for aquatic life.

Perform a Partial Water Change. Replacing part of the water in your tank is an effective and excellent way to reduce ammonia levels while keeping the tank clean. You should change a portion of the water about once a week or more often, depending on the condition of your tank. To check, you can use a fish net to gently stir the tank's substrate; if a lot of debris rises to the surface, you need to change the water more frequently.

• Let the new water sit overnight to reduce chlorine levels, or use a dechlorinator to treat the water.
• Wash your hands thoroughly to remove any soap, lotion, or contaminants, and dry them with a clean towel.
• Disconnect all electrical devices near the aquarium to avoid the risk of electric shock. Reconnect everything only after you’ve finished the water change and ensured everything is dry.
• For optimal water quality, you should replace about 30% of the tank's water. For example, in a 38L tank, you should replace 11.5L of water.
• You don’t need to move the fish to another tank while performing the water change, just be cautious not to startle them when you put your hands into the tank.
• Scrape off any algae growing on the tank walls. You can buy a professional algae scraper or use an old bank card for this task.
• Use a siphon to remove about 30% of the water from the tank into a bucket or another nearby container, then slowly add dechlorinated water back into the tank.

Remove All Excess Organic Matter from the Tank. Decaying organic matter is a major factor that causes ammonia levels to rise in the tank. You can use a fish net to remove everything from the tank except for the fish and live plants you want to keep. This helps lower ammonia levels and prevent further increases.

• Uneaten food significantly contributes to higher ammonia levels in the tank.
• Fish waste, as it decomposes, also increases ammonia concentration.
• Dead plants or fish release large amounts of ammonia into the water.
• Be sure to clean the filter to prevent organic matter from being pushed back into the tank. However, avoid changing the filter pad to maintain the bacterial balance in the water.

Reduce the Amount and Frequency of Feeding the Fish. If the fish do not finish their food, the leftover food in the tank could be contributing to higher ammonia levels. You can reduce this risk by limiting the amount of food left behind.

• Ensure the fish receive the proper amount of food. You may want to consult with a veterinarian or a fish expert to determine the right amount to feed your fish.
• Keep in mind that changing feeding habits will not immediately reduce high ammonia levels, but it can help prevent the levels from increasing after you perform a water change.

Add Beneficial Bacteria to the Water. Beneficial bacteria typically live at the bottom of the tank and help break down ammonia into relatively harmless nitrogen compounds. If your tank is new or the bacteria population has significantly decreased, you may experience what is known as "new tank syndrome" in the aquarium hobby.

• Some aquarium owners introduce beneficial bacteria by adding one or two inexpensive fish to the tank to utilize their waste as a source of bacteria. For this method, you could add goldfish to a cold-water tank, barbs (carp family) to a warm-water tank, or damselfish to a saltwater tank.
• Alternatively, you can introduce beneficial bacteria by adding gravel from an established tank to the bottom of the new tank.

Lower the pH in the Tank. Ammonia exists in two forms: non-ionized (NH3) and ionized as ammonium (NH4+). Non-ionized ammonia (NH3) is harmful to fish and tends to accumulate when the water's pH is more alkaline (higher pH values).

• Using pH-adjusting chemicals (available at pet stores) is perhaps the easiest way to lower the pH in the tank.
• Lowering the pH won't eliminate ammonia, but it can help reduce its harmful effects if you can't immediately perform a water change.
• A simple way to maintain lower pH in the tank is to use real gravel as substrate. Materials like crushed coral or coral sand release calcium into the water, which increases pH.

Increase Water Circulation. Ammonia in its NH3 form is a toxic gas that dissolves easily in water. Increasing water circulation in the tank can help diffuse ammonia gas from the water into the air.

• Increasing water circulation is not as effective in larger ponds, but it can help control ammonia levels in smaller aquariums.
• You can purchase air pumps at most pet stores or online.
• If you usually keep the aquarium covered, be sure to open the lid when aerating to allow ammonia gas to escape into the air.

Use a Neutralizing Solution. This method can temporarily help adjust ammonia levels in your aquarium. Neutralizing solutions are commonly sold at pet stores or can be ordered online.

• In reality, neutralizing solutions do not remove ammonia from the water; they simply neutralize the ammonia toxin, reducing its harmful effects in the water.
• You will still need a biological filter (containing beneficial bacteria) to convert ammonia into nitrites and nitrates.

Test the Tap Water. It’s rare for tap water to have excessively high ammonia levels, as most water systems test for chemical levels, such as ammonia, to ensure that the water is safe for drinking. However, if you've adjusted other factors and ammonia levels are still high, it's worth testing your tap water.

• You can use an ammonia test kit for aquarium water to check the tap water.
• If you discover high ammonia levels in your tap water, contact your local water supplier for further assistance.

Inspect Decomposition in the Aquarium. Decomposing substances in the aquarium are one of the primary reasons ammonia levels rise. You can address this issue by examining the materials in your tank.

• Any decomposing organic material, including aquatic plants and microorganisms, can increase ammonia levels when their protein structures break down.
• Uneaten food can also raise ammonia levels as it decomposes in the water.
• Be sure to quickly remove excess material from the tank and perform regular maintenance, such as full or partial water changes.

Understand That Fish Excrete Ammonia. If you notice a lot of fish waste floating in the tank, this may contribute to high ammonia levels. Fish waste decomposes over time, much like other organic materials, causing ammonia levels in the water to rise.

• You can manage the amount of fish waste by removing visible solid waste from the tank and performing regular full or partial water changes.

Purchase an Ammonia Test Kit. You can find these kits in most pet stores. The test kit will help you measure the overall ammonia levels (including both ammonia and ammonium), but it won’t distinguish between the two, so you may not be able to determine the exact toxicity of the water.

• Usually, if the aquarium contains fish and active bacteria, you won’t be able to measure ammonia levels accurately with the test kit.
• If the test kit detects ammonia levels and you're sure the tank has beneficial bacteria and no organic matter, the issue might be with the tank’s filter.

Measure the pH of the Water. The pH level of your tank can directly impact the ammonia concentration in the water. By regularly measuring the pH, you can ensure the ammonia levels don't reach toxic levels.

• The pH of the water influences the amount of ammonia molecules that are ionized or un-ionized.
• In addition to adjusting pH levels, you will still need to address the water using other methods, as increasing acidity won’t break down the existing ammonia molecules.

Test Water at the Right Time. Depending on when you test the water in your tank, the ammonia concentration reading might not be accurate. The best time to test is just before feeding the fish, before the food has a chance to break down.

• Ammonia levels will peak about 90 minutes after feeding the fish.
• Testing the water right after feeding (when the fish are expelling waste) might give you an inaccurate high ammonia reading.

• Ensure you don't overcrowd the tank with too many fish.
• Avoid overfeeding the fish and make sure you're using a good filter for the aquarium.
• It's recommended to establish the nitrogen cycle in a new tank before adding fish.