Ammonia in an aquarium: Part 1

These are the 3 best ways to get rid of ammonia from your fish tank:

1.  Add at least one more filtration system to your aquarium. This will at least double the amount of ammonia reducing bacteria in your aquarium.

2.  Use massive water changes to remove the ammonia ladened water and replace it with fresh, clean water.

3.  Wait. Move your fish to a second aquarium and then wait for the nitrifying bacteria in the first aquarium to grow abundant enough to lower the ammonia level to zero.

Ammonia is highly toxic to fish. The presence of ammonia can kill fish fairly quickly. I’ve seen this happen in as little as 24 hours. For example, about a year ago, a large snail I received died, and I didn’t see what had happened until one of my fish died out of the blue. 

Yep, I have had the same frustrating aquarium keeping problems as you might have had. 

One way to look at ammonia in an aquarium is to imagine that you are closed in a room filled with a strong concentration of ammonia in the air. Not a pleasant thought, is it? The gas would severely injure you if given enough time. Injuries could include blindness, skin burns, lung damage, and more. (https://www.mountsinai.org/health-library/poison/ammonia-poisoning )

So getting rid of ammonia naturally in an aquarium usually means increasing the nitrifying bacteria or changing out a large volume of water.

Picture Above – My planted freshwater 2.9 gallon nano aquarium

Ammonia in an aquarium:

The Invisible Threat: Keeping Your Aquarium Safe from Ammonia and Nitrite

I’ve always loved aquariums. The calming presence of fish gliding through a miniature underwater world is truly mesmerizing. But setting up my first tank was a rollercoaster ride. Sure, the décor was perfect, the fish looked vibrant, but something lurked beneath the surface – ammonia and nitrite. Nasty stuff, turns out, deadly to fish even in small amounts.

The Silent Danger: Ammonia and Fish Waste

Imagine my horror when I learned this invisible threat came from my fish themselves! Their waste breaks down into ammonia, which can burn their gills and cause organ damage. Yikes! Thankfully, there are these superhero bacteria that take up residence in the aquarium filter. They’re the nitrifying bacteria, and they gobble up the ammonia, converting it into something a little less scary – nitrite.

Building an Army: The Importance of Tank Cycling

But here’s the catch: these superhero bacteria need time to establish their colony. You can’t just dump a bunch of fish in and expect them to thrive. That’s where the magic of tank cycling comes in. It’s basically giving the good bacteria a head start by letting them grow in the tank without any fish. There are different ways to cycle a tank – you can add a sprinkle of ammonia yourself, or even borrow some filter media from a friend’s established tank to jumpstart the process.

Testing the Waters: Monitoring Ammonia and Nitrite Levels

The key during this cycling period is patience and vigilance. You become a water detective, constantly testing the levels of ammonia and nitrite. It’s like watching a race – the ammonia levels rise first, then the nitrite, as the different bacteria take over. But after a few weeks, things settle down. The good bacteria become a strong army, keeping ammonia and nitrite in check, making the tank a safe haven for your future finned friends.

Welcome Home, Fish! Maintaining a Healthy Aquarium

Finally, the moment arrives – adding fish! But remember, it’s not a free-for-all. Overcrowding or overfeeding can overwhelm the superhero bacteria, sending those ammonia levels spiking again. So regular water changes become your new routine, kind of like cleaning your house to keep it healthy.

Keeping an Eye Out: Monitoring Water Quality

Testing the water becomes second nature. Any traces of ammonia or nitrite are a red flag, prompting an investigation into my aquarium maintenance. Maybe I need a bigger filter, a water change, or to lay off the fish food for a bit. But the good news is, with a little care and attention, I can create a sparkling clean underwater world where my fish can thrive.

The Final Piece: Understanding Nitrate

There’s also this third player in the nitrogen cycle – nitrate. It’s the leftover product after the bacteria finish with the nitrite. Not as harmful, but still something to keep an eye on with water changes or plants that absorb it.

A Well-Kept Secret: The Danger of Well Water

And one last thing – well water can be a sneaky culprit. It might have too much nitrogen gas, which can be dangerous for fish. So, if I’m using well water, I have to take an extra step to de-gas it first.

The Reward: A Thriving Underwater World

All in all, keeping an aquarium is a balancing act. But by understanding the nitrogen cycle and becoming a water detective, I can create a thriving underwater world for my finned friends. It’s a constant learning process, but the reward – a healthy, vibrant aquarium – is absolutely worth it.

Ammonia in an aquarium: Part 3

The nitrogen cycle. Ammonia-oxidizing bacteria convert ammonia to nitrite, and nitrite-oxidizing bacteria convert nitrite to nitrate. Nitrate is a less toxic by-product of nitrification and has various fates depending on the type of aquaculture production system.

Figure 1. The nitrogen cycle. Ammonia-oxidizing bacteria convert ammonia to nitrite, and nitrite-oxidizing bacteria convert nitrite to nitrate. Nitrate is a less toxic by-product of nitrification and has various fates depending on the type of aquaculture production system.

Credit: UF/IFAS

Nitrite is toxic to fish at levels as low as 0.10 mg/L. Traditionally, nitrate has been considered non-toxic to fish even at levels up to 200 mg/L. However, more recent research is showing nitrate may be more detrimental than previously believed. In natural systems and ponds, nitrate is taken up as a fertilizer by plants, including phytoplankton, so levels typically remain low. In closed systems with little or no water exchange, however, nitrate can accumulate to higher than 250 mg/L. Water changes or separate denitrification systems are needed to remove nitrate from recirculating system water.

AMMONIA TESTING

All aquaculturists and hobbyists should invest in a dependable water quality test kit. A good water quality management program will reduce fish disease problems, promote growth, and lessen the need for chemical treatments. A water quality test kit will pay for itself many times over, both in numbers of fish saved and increased production.

Most commercial ammonia test kits measure the total ammonia nitrogen (TAN) in milligrams per liter (mg/L), which is the same as parts per million (ppm). Again, it is the un-ionized ammonia (or UIA) portion of the TAN that is more toxic. To determine the UIA fraction from the TAN measurement, the temperature and pH of the water must also be known. At high temperatures and high pH, there is more UIA. Therefore, a good ammonia test kit will include a TAN test, a pH test, and a thermometer.

There are two common types of ammonia test kits, and each uses a different testing method to determine TAN. One is the Nessler’s method and the other is the ammonia salicylate method. If formalin or formalin-containing products have been used in the water within 24–72 hours, the Nessler’s method will result in a falsely elevated ammonia reading. Use of ammonia binding products and many “water conditioners,” such as those used in pre-treating municipal water sources, will also cause false high ammonia readings with the Nessler’s method. This method also produces false reactions when used to test seawater. The reagent used in the Nessler’s method contains a small amount of mercury that in many states must be disposed of as hazardous waste.

The other testing method is the ammonia salicylate method. This method is not affected by ammonia binding products or formalin treatments. The ammonia salicylate method is also more accurate than the Nessler’s method when testing ammonia in seawater.

WHEN SHOULD AMMONIA BE TESTED?

In general, ammonia should be tested once a week in any production system. Ammonia (and other water quality parameters) should also be tested immediately any time fish appearance or behavior changes (including reduced feeding).

If multiple tanks depend upon a common biofilter (i.e., a recirculating system), there is no need to check every tank individually. A good practice is to consistently test the ammonia level in the tank with the highest feeding rate and spot test other tanks from time to time. Although a system shares a common filtration system, there can be some differences in water quality between tanks. If fish show any signs of abnormality, water quality should be tested immediately in that individual tank.

Keep records for all tests and monitor trends. Whenever ammonia is found, increase the frequency of testing until the problem is corrected. As mentioned previously, whenever fish are sick, test the water quality immediately.

Ammonia is likely responsible for more unexplained losses in aquaculture than any other water quality parameter. Because it is colorless and odorless at levels toxic to fish, the only way to know if it is present is to test for it. Fish submitted to a diagnostic laboratory are often tested for infectious diseases (bacteria, parasites, fungi or viruses) only. Even if a water sample is submitted to the laboratory for testing, it provides only a one-time evaluation that provides no insight into past trends. It is the responsibility of producers and aquarists to regularly test the water quality, which is very often the underlying problem. Fish may become sick even weeks after a water quality problem has been corrected, so a single, lab-tested sample cannot be used to fully evaluate the water quality effect on a fish disease problem.

INTERPRETING THE AMMONIA TEST

In healthy ponds and tanks, ammonia levels should always be zero. Presence of ammonia is an indication that the system is out of balance. Therefore, any ammonia in a pond or tank should alert the producer or aquarist to examine system management and to start corrective measures.

To determine UIA, three tests must be performed: TAN, pH, and temperature. Once these three parameters are measured, the fraction of UIA can be calculated using a multiplication factor found in Table 1. Find the measured temperature on the top row of the table and the measured pH in the left column. The number at which the appropriate column and row intersect in the table is multiplied by the measured TAN to give the UIA in mg/L. If temperature or pH falls between values on the table, round up to the next highest value to determine the “worst case scenario” because higher pH and temperature result in more UIA.

Anytime the UIA is higher than 0.05 mg/L, damage to fish tissues can occur. As the concentration rises above 0.05 mg/L, it causes more and more damage. At 2.0 mg/L, sensitive fish will typically die. Even if fish do not die directly from high ammonia levels, they become more susceptible to infectious disease. Again, any ammonia indicates a problem in your system. If you find it, take corrective measures immediately.

MANAGEMENT OF AN AMMONIA PROBLEM

The first thing to do when ammonia is present in a pond or tank is to reduce or stop feeding. Fish may not eat during periods of ammonia stress, and the uneaten feed will only make the situation worse. Reducing or stopping feed for a short period of time (e.g., 1–3 days) will not typically have a negative effect on fish (except fry). Overfeeding is a major cause of high ammonia concentrations, and stopping the feeding will allow the nitrogen cycle to “catch up” with the nutrient load. A 25% to 50% water change will help remove some ammonia, assuming the incoming water source does not contain ammonia. This process is only feasible in tanks or very small ponds, so do not try to solve an ammonia problem in a large pond using this method.

Low levels of dissolved oxygen limit the ability of nitrifying bacteria to convert ammonia and nitrite, so it is important to monitor dissolved oxygen and take steps to increase oxygen if it falls below 5 mg/L

In ponds, the addition of a phosphate fertilizer may help to relieve high TAN levels over a period of days by stimulating phytoplankton growth, which helps remove ammonia from the system; however, it may not help quickly enough in an acute ammonia crisis. Use a 0–20–0 fertilizer at a rate of 40 pounds per acre. It is important not to use a fertilizer that contains nitrogen because nitrogen will add to the problem. If phosphorus is not a limiting factor for algal growth in the pond, the phosphate fertilizer method will not work at all. Similarly, if the pond already has a heavy phytoplankton bloom, fertilizer should not be added.

In tank systems, water changes and the use of ammonia-binding products can alleviate ammonia toxicity in the short term. However, for long-term management, it is best to establish a properly designed and sized biofilter.

In tanks without a biofilter, the producer or aquarist should strongly consider incorporating one. Given the six to eight weeks necessary to establish a biofilter, this will not help in a crisis, but it is a long-term solution to the problem.Biofilters should be sized appropriately according to feed input.

With the exception of high-flow raceways, such as those used in the salmonid aquaculture industry, many flow-through tank systems do not have sufficient flow to eliminate ammonia adequately, so testing and management of ammonia in these systems is still critical.

Some chemicals used to treat diseases in fish, especially antibiotics, can be detrimental to the nitrifying bacteria in the biofilter. Both ammonia and nitrite levels should be tested more frequently after applying a disease treatment to ensure that the biofilter is still functioning appropriately.

SUMMARY

Ammonia is a major waste product of fish and is also produced as a breakdown of feed and other organics. It can accumulate in aquaculture or aquarium systems, where it will, at the very least, decrease production. It is frequently a stressor that leads to disease, and in other cases it kills fish directly. The only way to detect its presence is to test for it. A fish farmer or aquarist should invest in a dependable water quality test kit, learn how it works, and use it regularly.

Ammonia test kits only measure the total ammonia nitrogen (TAN). When this test indicates a reading above zero, producers or aquarists can determine the amount of the more toxic un-ionized ammonia (UIA) after measuring pH and water temperature. The multiplication factors are found in Table 1, and an example calculation is found in Figure 3. When ammonia is present, the fish in the system should not be fed (or feed should be reduced) until the problem is corrected. In small systems, a water change may help, and in large ponds, a 0–20–0 fertilizer may help.

Test for ammonia regularly and take corrective measures as soon as you detect it. Severe problems may occur when tests are not performed frequently enough. Even after an ammonia problem has been corrected, fish may become sick weeks later. Once fish begin to die, it is difficult to correct an ammonia problem without losing more fish.

RECOMMENDED

Fish Health Management Considerations in Recirculating Aquaculture Systems—Part 1: Introduction and General Principles (UF/IFAS Circular 120) https://edis.ifas.ufl.edu/FA099

Southern Regional Aquaculture Center publications, available at https://srac.tamu.edu/ 

Ammonia in Fish Ponds (SRAC Publication No. 463)

Nitrite in Fish Ponds (SRAC Publication No. 462)

Managing Ammonia in Fish Ponds (SRAC Publication No. 4603)

How to Start a Biofilter (SRAC Publication No. 4502)

Recirculating Aquaculture Tank Production Systems: An Overview of Critical Considerations (SRAC Publication No. 451)

Recirculating Aquaculture Tank Production Systems: Management of Recirculating Systems (SRAC Publication No. 452)

Recirculating Aquaculture Tank Production Systems: A Review of Current Design Practice (SRAC Publication No. 453)

REFERENCE

Emerson, K., R. C. Russo, R. E. Lund, and R. V. Thurston. 1975. “Aqueous Ammonia Equilibrium Calculations: Effects of pH and Temperature.” Journal of the Fisheries Research Board of Canada 32:2379–2383.

Table 1. Fraction of un-ionized ammonia in aqueous solution at different pH values and temperatures. Calculated from data in Emerson et al. (1975). To calculate the amount of un-ionized ammonia present, multiply the total ammonia nitrogen (TAN) by the appropriate factor selected from this table using the pH and temperature from your water sample