How to Reduce Ammonia in a Fish Tank

Ammonia is the unseen fish killer in your aquarium. Concentrations above 1.0 parts per million (ppm) can cause fish sickness and even death. The only safe levels of ammonia levels in your fish tank is zero ppm. Too many fish for your tank size, over feeding or excess waste create bacterial imbalances that lead to unsafe ammonia levels. Beneficial bacteria levels keep harmful ammonia and nitrites at safe levels in a well-maintained tank.

SeaChem Prime or Amquel Plus provide a quick but temporary fix to high ammonia levels. For a more permanent fix restore healthy ammonia eating bacteria balance by addressing the underlying cause of high ammonia levels such as over population, excess rotting food, dead fish, excessive poop or a dirty filter. Start by testing your tank’s water chemistry and then make adjustments to safe levels for your fish.

How Much Ammonia is Tolerable for my Fish?

Even low levels of ammonia in your fish tank will burn the gills of your fish. Higher levels of ammonia start a process called nitrate poisoning which stunts the growth of your fish, causes discoloration, inhibits reproduction, it damages the brain and organs of your fish until their highly stressed state leads to the development of disease and eventual death.

How do you Know the Ammonia Level is too High?

It is a good maintenance practice to check your ammonia levels at least once a week. Without regular testing you will likely not see the effects ammonia poisoning have on your fish until it is too late.

There are three types of water quality testers.

• The most precise are classified as scientific meter and probe. These scientific meters are the best of the best but range in price from several hundred to several thousand dollars.

• The most accurate and affordable way to test your water is with an aquarium test kit. The test kits are simple to use. Simply add some water from your fish tank to the included test tube and add a few drops of the testing solution, then shake. The water will change color, match the color of water in your test tube to your color card to see the ammonia level. For a helpful step-by-step guide please see our article, How to Test the Water in an Aquarium.

• There are ammonia test strips on the market as well, but they are not very accurate and only have a shelf life of about 2 years. After that time the test cannot guarantee any degree of accuracy. In addition, their limited accuracy is reduced when the strips are exposed to moisture, stored improperly or if you touch the testing pad with your finger. When you factor in the cost of each strip compared to the number of tests you can perform from the test tube option, you will find that test strips are by far the most expensive option on the market.

Timing of Water Testing is Important

Avoid artificially high readings by testing the water at night before feeding. Earlier feeding will have had the chance to break down in the water. In general, testing your water shortly after your fish have had a meal and started producing waste will result in inaccurately high ammonia readings. It takes about 90 minutes after feeding for ammonia levels to peak.

If Ammonia Levels are High, what do I do First?

If your ammonia levels are high enough to be fatal to your fish, it may be best to dose your tank with ammonia neutralizing drops to improve your fish survival while you work through identifying and resolving the causes of high ammonia levels.

In this high ammonia condition, we also recommend the temporary use of a zeolite water filter formulated for aquarium use. Zeolite water filters are highly effective at absorbing ammonia but should be used temporarily to address the immediate high ammonia problem.

Long term use may lead to starving your beneficial bacteria of food leading to a significant population reduction of established bacteria colonies or may stunt the development of healthy bacteria in a new tank. In other words, long term use may inhibit the essential and natural process of the nitrogen cycle.

Determine the Cause of High Ammonia Levels in your Fish Tank

Now check for these potential causes:

1. Look for uneaten food on the bottom of the fish tank.
   • Your fish should eat all the food you feed them within 20 minutes. If there is still food floating in or on top of the water after 20 minutes then you are feeding them too much. This leaves the uneaten food to settle, rot and will produce rising ammonia levels. You can fix this with a vacuum gravel cleaner followed by a 25% water change.
2. Look for waste material in the fish tank.
   • If you see fish poop floating in the water or on the bottom of your fish tank, then the beneficial bacteria are probably not sufficient to keep up with the bio load. The excessive poop will decompose, releasing ammonia into the water. You can fix this by using a fish net and scooping out any floating poop in the water and then clean the bottom of the tank with a vacuum gravel cleaner followed by a 25% water change.
   • Decomposing aquatic plants and microorganisms can sharply raise ammonia levels as their protein matrix break down. Use plant snips to cut the dead or dying leaves from your living plants. Use a fish net to remove any remaining plant leaves and debris from the bottom of the tank.
3. Look for dead fish.
   • You want to remove dead fish from your fish tank as soon as possible. Dead fish left in your tank may significantly spike ammonia levels in your fish tank but are not always noticed right away if they become stuck in plants, behind decorations or to the intake of your water filter.
   • If your fish died because of an illness, the longer the dead fish remains in the water the greater the likelihood of spreading the disease especially as remaining fish may eat portions of the dead rotting fish. Use a fish net to remove any dead fish followed by a 25% water change.
4. Your water conditioner may be creating ammonia.
   • Many water conditioners designed to eliminate chlorine and chloramines accomplish this by chemically breaking down those chemicals. The by-product of these de-chlorinating chemicals is the creation of ammonia! The chemical companies hope that the increased ammonia will be filtered or eaten by the well-established beneficial bacteria faster than the ammonia can kill your fish.
   • Use SeaChem Prime or Amquel Plus as they are well engineered products designed to neutralize the harmful effects of ammonia. In addition to detoxifying ammonia, they also remove chlorine, chloramine, nitrate, nitrite and fish pheromones.
5. You may not have enough beneficial bacteria to keep up with ammonia production
   • If your tank is new the bacteria colony may not have matured enough to keep up with ammonia levels. If you have over-cleaned your tank and removed too much of the beneficial bacteria in the process, you may be suffering from “new tank syndrome”.  You can “seed” your new tank with gravel or substrate from an established tank to expedite the growth of beneficial bacteria.
   • When cleaning your fish tank, you should delay the final step of cleaning or replacing the filter by one or two weeks. This will allow the established bacteria in the filter to take hold throughout the rest of the tank.
6. Your fish tank water pH is too high
   • Most freshwater tropical fish thrive at a pH of 6.8 to 7.6, however some species of fish vary from these averages. High pH levels tend to change the polarity of ionized charged ammonia particles (NH4) which is non-toxic to fish (unless at extremely high levels) and convert it to de-ionize ammonia (NH3) which is very toxic to fish.
   • Test your water to establish a pH baseline then add chemical pH drops to lower your levels to a safe range. Lowering your pH will not remove ammonia but it will help to maintain the less toxic ionized form of ammonia between water changes, biological filtration and bacterial consumption of ammonia.

1. Fish tank ammonia gas diffuses too slowly
   • The NH3 form of ammonia is a fish toxic dissolved gas that permeates the water. The surface tension created by stone diffused air bubbles throughout your tank pushes NH3 to the surface of your aquarium water.
   • The aeration of ammonia from your fish tank water is best accomplished by removing the lid from the top of the tank and exposing as much water to the surface air as possible.