How to get rid of ammonia in fish tank

Ammonia is bad news for your fish. If you’ve got high levels of ammonia in your tank - or even anything above 0 parts per million (ppm), this will prove to be deadly to your fish. The good news is that if you’ve been monitoring your aquarium’s ammonia levels regularly, you’ll be able to catch it before it harms all of your fish.

Any ammonia spike in your aquarium needs to be dealt with as swiftly as possible. The best way to tackle this is to use a combination of tactics: change the water in your aquarium; feed your fish less food; clean your filter; add products that can reduce ammonia. We’ll discuss all of these in more detail below!

Why is ammonia bad for your fish?

The ideal level of ammonia in your aquarium is 0ppm. Anything more than this is incredibly harmful for your fish - it can make their gills stick together, so that they can’t breathe. At low levels, ammonia will burn the gills of your fish, causing them distress. 

As the levels of ammonia gradually rise - if unchecked - it will cause damage to your fish’s organs and brain, until they eventually die. 

Some fish have a higher tolerance of ammonia, but you shouldn’t rely on this to keep them happy and safe. Instead, by constantly monitoring the state of your aquarium water, you can ensure that your fish have a safe environment for them to swim happily in.

What causes ammonia in my aquarium?

Not sure how all that ammonia got in your tank in the first place? It’s all down to the nitrogen cycle. 

All ammonia will be caused by the biological load - or bioload - that you have in your tank. This will be your fish waste, any dead plant matter you have accumulated in the tank, and any extra food that goes uneaten. The more biological matter you have in your tank, the more bioload you have. This all gets turned into ammonia when it breaks down - which is where proper filtration comes in.

Other factors which might have caused ammonia to start being produced in your tank could be that you’ve added your fish too early; added too many fish to a tank; you didn’t wait for the tank to cycle properly before adding your fish; you might be overcleaning your filter; your filter isn’t powerful enough for the number of fish you have or for the size of your tank; you’re overfeeding your fish; you’re not performing regular maintenance.

If your tank is being properly filtered by a good quality filter, then the ammonia will gradually be turned into nitrite, then nitrate. These other chemicals aren’t great for your fish either, so it’s important to replace the water in your tank regularly.

But how do filters help to reduce the ammonia in your tank? That’s because you have biological media in your filter - usually little rocks or ceramics - which harbor helpful bacteria. These helpful bacteria help to break down ammonia, turning it into nitrite, and then nitrate.

Good filtration is key

If you’re serious about your fish, you’ll want to make sure you’ve got the best filter for your aquarium. The better the filter, the healthier your tank’s environment will be, and the happier your fish will be as a result.

A canister filter is better than a cartridge filter when it comes to taking care of the ammonia in your tank. That’s because with cartridge filters you need to replace the cartridge every two weeks, which means that by the time your friendly bacteria has built up in order to do the job properly, you’re throwing them out.

Instead, look for a filter that has cartridges you don’t need to change. If in doubt, it’s always better to invest in two filters for your aquarium - that way if one fails, you know you have the other filter to rely on to keep your fish safe.

The only time you don’t need to worry about high levels of ammonia is when you’re first setting up a new tank - without any fish in it - and your filter is just starting to build up the good bacteria you need in order for it to do its job properly. 

If the level of ammonia is still high after you’ve cycled your new tank, don’t stress - simply leave it to continue cycling for at least another week. Keep checking the ammonia levels in your tank before you add any fish at all.

How to test your aquarium for ammonia

The best and most efficient way to test your fish tank’s level of ammonia is to invest in a testing kit. There aren’t really many other reliable ways to check for ammonia without them, and they’re a relatively inexpensive piece of kit. It’s a good idea to keep some to hand just in case, as you should be checking your aquarium at least once a week.

The API testing kits are easy to use. Simply add aquarium water to the test tube, as well as a few drops of the testing solution, then shake. Once the water has changed color, measure it against the color chart to see what the level of ammonia is like in your tank.

The ideal amount of ammonia you should have in your fish tank is 0ppm. Unfortunately, this isn’t always the case, and there are numerous factors which come into play to cause ammonia spikes. Anything between 0ppm and 2ppm is a fairly common problem, but is easy to help solve. Anything above 2ppm should be treated as an emergency, because otherwise, your fish could die.

How to get rid of ammonia from your fish tank

The first thing to remember if you’ve got ammonia in your tank is not to panic. There are several things you can do to reduce the ammonia levels so as to save your fish. If your ammonia levels are more than 2ppm, it might be worth considering temporarily moving your fish to another tank so as to allow you to get things back to normal for them.

One of the first things you should do is to change the water in your tank. If you’ve got less than 2ppm ammonia in your tank, you should do a 10% water change daily for up to a week, then measure your ammonia levels again. If you’ve got a big ammonia spike in your tank, you’ll need to change up to 90-95% of the water in order to save your fish. 

The general rule tends to be at least a 50% water change so as to reduce the ammonia in your tank. Replacing the ammonia riddled water with fresh water will help to reduce the amount of ammonia to much more manageable levels, giving your filter the chance to catch up.

Next, you should reduce the amount of food you give your fish dramatically. Only give them as much food as they can consume within the space of three minutes - anything that gets leftover will drift to the bottom of the tank and start to biodegrade into ammonia or get stuck in your filter, preventing it from doing its job properly.

Check your tank for any dead or decaying plant matter, or dead fish. These will break down over time, making your ammonia problem worse. A good thing to do is check your tank for these when you clean your filters. Remember to check under rocks and in nooks and crannies, because dead fish could be hiding out of sight - especially in a large community tank. It’s also a good idea to take this time to vacuum your gravel; any leftover food will have collected here. You can also vacuum your gravel any time you change the water in your tank.

Take a look and ensure that your filter is working properly. Unclog it if it has become clogged - if water isn’t flowing freely over your biomedia, then the bacteria won’t be able to do their job and remove the ammonia from your tank. Remember to check your cartridges, filter tubes, impellers, and media. Make sure that you clean your filter properly to keep it working correctly.

In extreme cases, you may need to add a water conditioner or other such chemicals to your water in order to prevent the ammonia from killing your fish. These types of products will help to neutralize the ammonia until you can find the source of the spike. It’s important to remember that this final solution is a temporary fix - you should aim to find the source of the ammonia spike so as to ensure that it doesn’t happen again.

The types of products you should invest in are Seachem Prime and Microbe-Lift. Seachem Prime will reduce the toxicity of your fish tank’s water until you can find the source of the spike. Microbe-Lift is a good product to use both in the event of an ammonia spike, and also to try and prevent it from occurring in the first place. That’s because it encourages the bacteria in your filter to mature, meaning they’ll be better equipped to deal with the ammonia in your tank.

If your tank has had a big ammonia spike, it may take around a week or longer for the aquarium to return to normal.

How to clean your filter

To keep your filter working as it should, you’ll need to make sure that you’re cleaning it properly. However, ‘clean’ is a deceptive word when it comes to your filter, as you’ll want to avoid using any kind of soaps, detergents, or even tap water, as these will kill the friendly bacteria you want to keep in your filter. Soap will also leave residue in your aquarium, which will make it inhospitable for your fish.

Once you’ve ‘cleaned’ your filter, the water in your tank may appear cloudy. This is simply a bacteria boom and may indicate that there are ammonia and nitrate in your water. Make sure to check your water levels.

You should be cleaning your filter’s sponge in a bucket of aquarium water every 1-2 months. Get all of the gunk out - the aim is to remove the waste but to keep the bacteria that has built up. 

Every 6 months, you should be removing any build-up of waste in your biomedia by washing it in a bucket of aquarium water. It’s important to remember not to clean both your sponges and your biomedia at the same time, as you’ll be running the risk of getting rid of too much bacteria.

You should replace your biomedia and sponges every 6 months to 2 years when they start to show signs of breaking down. As long as you make sure to carry out regular maintenance so that your filter can work properly in your tank, you should be able to keep your aquarium’s water clear. Remember not to overclean your fish tank, too!

Prevention is the best cure

While the above tips will help you to deal with an ammonia spike, prevention is the best cure. You will need to make sure that you are cleaning your filter properly; that you’re only feeding your fish as much food as they can eat within the span of 3 minutes; that you haven’t got too many fish in your tank; that you have the proper filter in place to deal with the size of your tank.