While there are plenty of chemical imbalances that affect your aquarium water quality, Ammonia has to be near the top. At Swell UK, we receive plenty of calls and queries about ammonia levels, and rightly so! Ammonia in your tank cannot be completely avoided and needs to be regulated with filtration to avoid poisoning your fish, affecting pH and creating blooms of nasty looking algae.

First and foremost, you can test for ammonia levels using a test kit.

What causes ammonia build up in my aquarium?

Ammonia is a natural product of the life in your fish tank. It is produced in the biological waste from your fish and other aquatic life, as well as the degradation of other previously living matter like fish food.

It is effectively (if you want to place a starting point on a circular process), the first stage of the nitrogen cycle in your aquarium, wherein a healthy cycle, ammonia produced by your fish is turned into nitrites (also bad), and then Nitrates (not so bad), before being used by some of the plants in your aquarium or being removed in water changes.

What’s so bad about ammonia?

Having too much ammonia in your water is definitely a bad thing. High levels of this stuff can burn your fish’s scales and skin, as well as inhibit their gills from filtering oxygen into their bloodstream, burning and suffocating them at the same time!

Furthermore, high ammonia levels are likely to cause big algae problems in your tank, meaning your well cultivated, well-groomed tank is going to take on a green tinge pretty soon if you can’t get on top of it quickly, possibly taking you months to recover from. It can also affect pH levels too, throwing everything out of sync in your tank.

What can I do about it?

Good ammonia control ideally starts from when you first set up your aquarium. In a healthy, mature tank your filter system should be able to handle the amount of ammonia created by your fish stock. Choosing an adequate filter system with good biological media is the first step, ensuring your filter has a large surface area to develop a healthy culture of nitrifying bacteria to break down the ammonia into less harmful substances.

When starting your tank, you can help mature your filter safely by conducting a routine of fishless cycling. This is where you start running your tank with NO FISH so no ammonia is produced naturally, allowing you to use filter start additives and ammonia buffers to ease your filter media into healthy growth of bacteria.

Once you have established this cycle and your filter is more mature, you can stop adding ammonia manually and begin adding fish. Do this slowly, easing your filter into the process and be careful not to overstock and give your filter something it can’t handle. Setting up your tank this way will hopefully mean you avoid the worst of New Tank Syndrome, however you should test your water regularly during this period.

For tanks that were previously fine, you need to look at other causes of ammonia. It could be that your new live-additions to the tank are now creating too much ammonia for your existing filter to handle, in which case you may need to sell a few or give some away to a good home.

Overfeeding may also be an issue. Remember, only feed your fish for 2 minutes at a time, and be sure to remove any uneaten food from the tank before it decays and enters the nitrogen cycle as ammonia.

Green water treatments and UV clarifiers can help get rid of the algae bloom that is likely to develop, but the cause of the problem will always be the ammonia levels. More regular water changes can help combat this, but the bottom line is the relationship between your ammonia production and your filter’s ability to handle it. Consider a filter upgrade if all else fails!

But most of all – good luck! Ammonia issues are a part of fish keeping, and there are few aquarists who can truly claim that they have never suffered at some point. But with regular testing and careful, methodical water keeping, you stand as good a chance as the best keeper.