One of the aquarium health issues that we address most frequently at Aquariadise is ammonia poisoning. Even at low levels, ammonia and nitrites are incredibly toxic to fish, and should be kept at zero at all times.
Thankfully, with a bit of biological know-how, you can create a healthy nitrogen cycle within your tank to keep water conditions healthy and ammonia-free.
Here, we’ll share how.
Key Takeaways
- Ammonia is extremely toxic to fish but can be kept at safe levels by fostering beneficial bacteria to convert it to less toxic nitrates via the ‘nitrogen cycle’.
- If the nitrogen cycle fails, ‘ammonia spikes’ can quickly become fatal. An urgent response is critical to save your fish’s lives.
- A healthy nitrogen cycle can be maintained by regular tank cleaning, avoiding overfeeding, and maintaining an efficient aquarium filter.
What Is Ammonia?
Ammonia (NH3) is a chemical compound that is produced by decaying organic matter such as dead plants, decaying detritus and algae, leftover food, and fish waste in the aquarium.
At high levels, ammonia poisoning can quickly set in and affect all the organisms in your aquarium. Because of this, it is important to fully cycle a new fish tank and establish a biological filter.
The Aquarium Nitrogen Cycle
The aquarium nitrogen cycle consists of two stages: First ammonia is turned into nitrite that is then turned into nitrate by beneficial bacteria colonies populating the aquarium.
In a new tank, a source of ammonia is needed to jumpstart the cycle. Various aquarium-specific products may be used to dose ammonia or pure ammonia may be added. Otherwise, another popular method is to ‘ghost feed’ which essentially allows uneaten food to decay and release ammonia.
Nitrifying bacteria will then perform nitrification which converts this ammonia to nitrites (NO2). These nitrites are then converted by another type of nitrifying bacteria into nitrates (NO3) which can be more easily taken up by live plants and other organisms.
While nitrate is also toxic in large doses, it is safe for most fish at concentrations below 0.20ppm
What Does Ammonia Do in the Aquarium?
While ammonia might immediately seem like a bad thing to have in the aquarium, it is food for many microorganisms and plants.
Once the fish tank has been cycled, ammonia enters the system by way of fish waste, uneaten food, and decaying organic matter. This then needs to be converted by the good bacteria in your fish tank.
In return, this bacteria feeds on the ammonia, reducing ammonia levels in your tank and keeping fish from ammonia poisoning. In addition, aquarium plants can readily take up ammonia, nitrite, and nitrate to grow, further lowering nitrogen compound levels throughout the tank.
What causes ammonia in the fish tank?
Now that we know what ammonia is, how does it get into our fish tank systems? There’s usually a clear cause for ammonia levels being in our tanks, but sometimes the cause might be the source water, which we’ll discuss later.
However, the main causes of an ammonia problem stem from organic die-off, overfeeding, overcrowding, or poor fish tank maintenance.
Die-off
Die-off is one of the biggest factors influencing the ammonia levels in your fish tank. Organic matter starts to decay and rot, which can lead to an overload of nutrients flooding the water column, including ammonia.
A dead fish will start to affect water quality after just a few hours. It is important to take count of all your tropical fish and invertebrates daily to make sure that a dead fish doesn’t start to decay in hard-to-reach spaces; all invertebrates should be accounted for as well. There is the chance that, given an efficient cleanup crew, you might not even have time to find the dead fish or invertebrate as the remains have already been consumed otherwise. However, it is still best to remove dead livestock when you see it.
Plants may start to decompose, which can also raise ammonia levels in the tank. While some members of the cleanup crew might be able to handle small plant die-offs, it is usually best to prune the plant before rot sets in and begins to produce ammonia.
If you transfer live filter media or other decor from another fish tank, you will likely experience some die-off; this is how some saltwater fish hobbyists begin their cycle with live rock. Due to changes in water quality and potential exposure to the air for too long, organic material starts to die off during the transfer. This usually leads to a traceable spike in ammonia in the fish tank over the next few days.
Overfeeding
Overfeeding can be just as dangerous as having a dead fish left in the tank. More directly, uneaten fish food breaks down and releases nutrients into the water column; uneaten food can also start to rot if left in the fish tank for too long and produce ammonia.
Believe it or not, many fish don’t need to be fed that often; while most hobbyists likely to give their fish 2-3 feedings a day, it’s not entirely necessary, especially if the food is high in protein. More importantly, it is better to give a larger variety of high-quality foods in smaller portions rather than feeding more often with food that has little to no nutritional value.
As a general rule, only feed fish as much as they can eat in a couple of minutes and remove the excess; uneaten food is very likely to get stuck in filter pads, which can easily lead to ammonia leaking into the fish tank.
Overcrowding
Similar to overfeeding, overcrowding not only increases the amount of uneaten food entering the system but also the direct waste as a result of having that many more fish. Too many fish directly results in too much ammonia in the water, which can quickly lead to conditions that are toxic to fish and invertebrates; even worse, if these fish die, then they can create an ammonia spike due to decaying organic matter.
For freshwater fish, it is recommended to only have one inch (2.5 cm) of fish per gallon (3.8 L) of water. More than this can and will lead to too much waste as well as a depletion of dissolved oxygen as more fish means less oxygen and more carbon dioxide.
Poor Fish Tank Maintenance
Lastly, a high ammonia level in the fish tank can be the result of poor maintenance. In general, it is recommended to perform partial water changes every week or every other week in a typical fish tank to keep nutrients down. Vacuuming the substrate also helps remove stuck organic matter and keeps anoxic areas from building up in the gravel or sand, which could potentially lead to nutrients leaking out later.
As we’ll discuss later, a simple water change is the best way of reducing ammonia levels in the aquarium; however, it’s best to keep on top of the problem by performing regular tank maintenance instead of waiting for the problem to present itself!
What Are the Symptoms of Ammonia in a Fish Tank?
If you suspect ammonia in your fish tank, you must immediately test your water to confirm the problem. Here are the signs that there could be an issue:
Odor
Fish tanks have a particular smell, but so does ammonia. One of the quickest ways to see if ammonia is in your tank is by taking a quick smell.
If you’re unfamiliar with what ammonia smells like, it is often likened to the odor of cat urine. The odor is crisp and foul-smelling, close to that of vinegar but still more fragrant.
This smell will intensify with the level of ammonia present, but in general, ammonia is detectable by scent in relatively small amounts.
Fish Behavior
Besides the odor, fish behavior will be the telltale sign that ammonia is starting to affect livestock.
Ammonia poisoning can happen relatively quickly and can lead to a slow and painful death for fish, invertebrates, corals, and even plants.
The main signs you will want to look out for are lethargy, gasping for air, and redness around the gills.
Lethargy
High levels of ammonia can directly burn the internal and external anatomy of your fish.
The gills are usually affected the most and can start to overcompensate with mucus to try to relieve the burn. This ultimately leads to a lesser ability to absorb oxygen and a loss of appetite.
Swimming becomes painful and exhaustive, leaving your fish tired or maybe even motionless at the bottom of your tank.
Gasping for Air
Along with lethargy, you might find that your fish is struggling to breathe. This is due to the mucus that has been generated to help relieve the burns as well as damage to the gills and internal organs.
In a tank with high ammonia levels, it is common to see fish breathing heavily and gasping for air. They will usually alternate between resting on the substrate and breathing heavily and gasping for air towards the top of the fish tank where dissolved oxygen concentration is highest.
Redness Around Gills
It’s possible that your fish doesn’t display any of the aforementioned symptoms, but develops redness around its gills instead. This is due to the damage being done in and around the gills.
These red spots can also appear across the body as the ammonia continues to burn. Along with being excruciatingly painful, these sores can become infected and lead to an even bigger problem.
What Are the Best Ammonia Removers for Aquariums?
There are a few ways to lower ammonia levels in the fish tank, all of which can be pretty easily done.
If you haven’t yet traced the source of the problem, keep looking for the cause of the ammonia spike. Ammonia will continue to be introduced into the water if, for example, something has died in the tank or if the aquarium is overcrowded.
Water Changes
One of the easiest and most efficient ways of lowering ammonia levels is by performing partial water changes. Water changes immediately remove ammonia from the fish tank and introduce safe water that will help dilute the remaining ammonia in the system.
It’s important to space water changes out over a couple of days to make sure that any fish or invertebrates aren’t being more stressed than they already are.
Once you have tested your water quality and found that ammonia is the problem, it is best to perform a large water change of 40-50%. Allow the system to realign and test the parameters the next day.
If ammonia is still present, perform another partial water change of about 20-30%. Allow another day and test the water again. Perform partial water changes as needed until ammonia returns to 0 ppm.
Aquarium Supplement
Water changes are usually the easiest way to solve a high ammonia level, but biological and chemical supplements may sometimes be necessary and can be helpful to speed along a new tank.
Water Conditioners
One of the best products to have on hand at any given point is a water conditioner such as Seachem Prime that removes chlorine as well as detoxifies ammonia, nitrite, and other heavy metals.
While this won’t solve the cause of the problem, fish and other livestock should be affected less, and more time will be given to figure out the root cause.
Beneficial Bacteria
Many beneficial bacteria products that may be introduced into your aquarium to help keep nutrients at ideal ranges. However, these biological supplements will not immediately reduce ammonia levels.
Instead, good bacteria is added into the aquarium to help accelerate the nitrogen cycle and process ammonia over the next few days.
Replace Your Filter Media
Ammonia spikes are often caused by a colony collapse of nitrifying bacteria on your filter sponge.
Therefore, replacing it with one from a healthy, cycled aquarium should help to reboot the nitrogen cycle and reduce ammonia over the coming days.
How Long Does It Take To Lower Ammonia Levels in the Fish Tank?
The problem with having ammonia in your tank is that you need to remove it as soon as possible all while not stressing out your fish even more.
With prompt water changes and chemical intervention, ammonia can usually return to safe levels within a day or two. Low levels can be solved with a simple water change, while higher levels might need several water changes and chemical support.
Whether ammonia levels remain at safe levels, however, depends on whether you’ve solved the root cause of the problem, and prevented it from returning.
How Do You Prevent Ammonia in Your Aquarium?
Test Kits
If you don’t know what’s happening with the chemistry of your fish tank, then you don’t know what’s happening biologically.
Testing for ammonia, nitrites, and nitrates is recommended every month for established aquariums, and more frequently in young tanks. Doing so will help you to identify any issues early on, so you can work on solving them quickly.
Test Your Source Water
Occasionally, ammonia may be present in tap water. If you have an ammonia problem, it’s worth testing your tap water to be on the safe side.
Keeping Live Plants
Aquarium plants tend to favor nitrate (NO3) as their main essential nutrient, though they are also able to uptake ammonia (NH3), ammonium (NH4), and nitrite (NO2).
In my experience, well-maintained live plants are an excellent way to help keep your water in a healthy equilibrium – just be sure to remove dead leaves to prevent them from rotting and releasing ammonia into the water.
Conclusion
If your aquarium has suffered an ammonia spike, you need to work quickly to save your fish’s lives. Partial water changes and chemical supplements are good emergency fixes, but you must also solve the root cause of the problem to prevent it from happening again.
Avoiding overfeeding, regular tank cleaning and good filtration maintenance are all essential to keeping ammonia levels at zero.
