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How To Check Ammonia Levels In A Fish Tank Without A Kit?

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We all know that ammonia is bad for fish. Unfortunately, it is pretty common to get stuck in a tricky situation without a test kit. As it happened to me in the past, I decided to dedicate an entire article explaining how you can check for ammonia without any products.

You can roughly tell that the ammonia levels are higher than 0 ppm if your fish are breathing heavily, seem lethargic, and develop red patches resembling bleeding. You may also notice that your water is cloudy and smell like rotten eggs.

As we move forward, I will elaborate on some valuable signs that may indicate the ammonia levels in your tank are high. That will allow you to catch the situation in time, even before buying a test kit.

Still curious? Feel free to check my complete guide on aquarium ammonia, where I discussed what causes ammonia, how to get rid of it, what equipment to use, and much more.

How To Check Ammonia Levels In A Fish Tank Without A Kit?

You cannot set up an aquarium without a testing kit. You must cycle the tank before introducing the fish, and you can’t expect to navigate the nitrogen cycle without a testing kit.

However, once you have a stable aquarium with the correct parameters, you can get by without testing strips and kits. But you have to take the following into account:

1. The Behavior & Appearance Of Your Fish

Have you heard the terms ‘Ammonia Stress’ and ‘Ammonia Poisoning?’ People use them interchangeably, and they are right. They refer to the same thing. 

However, aquarists only use ‘Ammonia Poisoning’ when a fish dies. They will attribute the creature’s death to Ammonia poisoning.

On the other hand, if the fish is alive but it has started manifesting the negative consequences of high ammonia concentration, aquarists will blame these symptoms on ammonia stress. 

Ammonia stress is not pleasant for fish. However, it can also alert you to the presence of ammonia. 

Naturally, a testing kit is better because it can warn tank owners about rising ammonia levels before the fish suffers. 

Yet, in the absence of a testing kit, you can use a fish’s symptoms to identify ammonia spikes. That includes the following:

  • Gills

Have you looked at the gills? Ammonia stress encourages gasping in fish because ammonia burns their gills, compromising their ability to extract oxygen from the water.[1]

If your fish are gasping for breath, perform a water change. If their behavior improves, you can blame the gasping on high ammonia concentration. 

  • Lethargy

Ammonia stress makes fish sick. Like every living creature, sick fish are less active. They will spend their days lying at the bottom of the tank, either because of the stress or because the ammonia has exposed the creatures to diseases that have sapped their strength. 

Lethargy is common among fish in aquariums with a lot of ammonia because they don’t eat. Their appetite will fade gradually in response to their failing body functions until they stop eating altogether. 

  • Patches

Ammonia burns are difficult to ignore. You will see them all over the fish’s body, including the gills. The creature may look like it’s bleeding.[2] Those red streaks will become more pronounced until the fish dies.

Waiting for the fish to display signs of ammonia poisoning is dangerous because the fish may die before you can take steps to save it. 

Ammonia can have destructive side effects, increasing respiratory activity, affecting the creature’s balance, causing convulsions, and more.[3]

Therefore, you should apply caution. Take action and change the water when your fish display behavior you don’t recognize. However, you can’t change the water too frequently. Find a balance.

2. Take A Sample To The Fish Store

Some people have testing kits but don’t know how to use them. As such, they rely on fish stores. If you take a sample of your water to a local retailer, they will test it for ammonia.

This option is time-consuming and inconvenient, but it works. You can submit a sample of your aquarium’s water for testing every week, depending on the cost.

While this service is free in some places, many stores charge a monthly fee. But it wouldn’t make sense to pay this fee when it is so much cheaper to buy testing kits.

3. The Water Will Be Cloudy

Cloudy water worries most aquarists because they typically assume the worst. However, cloudy water isn’t necessarily harmful.

First of all, new aquariums can become murky because of the proliferation of nitrifying bacteria that turns ammonia into nitrites and nitrates.[4]

The bacteria will cover the walls and decorations in a slimy biofilm. When the ammonia starts turning into nitrite, the water will clear. If it doesn’t, you have to consider other culprits, including:

  • Gravel – If you did a poor job of washing the gravel, it would make the water cloudy. You have to start afresh. Drain the water and wash the gravel.
  • Minerals – The water has too many heavy metals, phosphates, silicates, and the like. You have to treat the aquarium with conditioners. You can also use reverse osmosis.[5]
  • Waste – If you permit leftovers, waste, and dead organisms to decompose, the water will turn cloudy.

Waste, leftovers, and dead organisms are your biggest concern because they generate ammonia after decomposing. 

For that reason, many aquarists blame cloudy water on ammonia. They are more likely to perform a water change in a tank with cloudy water. 

You should wait a little while before panicking. Give it ten days. If the water doesn’t clear, you can take action. 

4. The Water Will Stink

Does your tank smell? A foul odor is not necessarily a sign of ammonia. However, it should concern you because bad smells have several problematic sources, including:

  • Dead Fish

Dead fish are going to smell. The fact that they are underwater doesn’t change anything. Once they start rotting, you will notice the abhorrent scent.

This is why amateur aquarists have to learn to perform a roll call. Count your fish. The current can carry dead fish to distant nooks and crannies where you won’t find them until they decompose and destroy the balance in the tank.

If your fish population has gone down, take that as a sign that a fish has died. You can confirm your theory by smelling the water. Dead fish will raise the ammonia concentration unless you remove them.

  • Food 

Dead fish are not the only things that can smell. If you allow leftovers to remain in the tank, they will create a disgusting odor once they rot.

If you have a poor maintenance routine, the smell will grow with each passing day as the volume of leftovers increases.[6]

  • Waste

Like leftovers, fish waste will rot, producing a foul scent that can act as a warning sign, compelling the aquarist to act before the ammonia concentration rises and harms the fish.

  • Plants

When aquarium plants die, they rot. They are easy to spot because they usually turn black or brown. Like dead fish, dead plants produce ammonia when they decompose. They will contribute to the foul smell in the tank.

As you can see, every factor that adds to the foul smell emerging from your tank will also raise the ammonia concentration. Therefore, you have every reason to treat bad smells in aquariums as signs of ammonia.

How High Is The Ammonia If I See These Signs?

It is impossible to determine the precise ammonia level without a testing kit. That is because anything above 0 ppm can cause issues.

However, many fish can tolerate and show no symptoms at 0.25 ppm and lower, especially if they have been exposed to these levels for a while.

So, if your fish seem in distress, you can assume that the ammonia level is 0.25 or higher. But that is a rough estimation. Many fish will present symptoms even at 0.25 or lower.

Either way, trying to guess the ammonia levels is bad practice. As a rule of thumb, I suggest you get yourself a test kit.

I personally use the API FRESHWATER MASTER TEST KIT (link to Amazon). That is the most reliable I have found so far. It also lasts for about eight hundred measures, making it pretty cost-effective.

What Should I Do If I Suspect The Ammonia Is High?

Even if you don’t have a testing kit, watching the signs above requires you to step in. This is what you should do:

  • Get yourself a test kit.
  • Perform a 25 to 30 percent water change to dilute the ammonia.
  • Get the API AMMO-LOCK (link to Amazon)
  • Add 5 ml per 10 gallons every two days until the ammonia is no longer detected.
  • Install an air stone and vacuum the substrate.

Installing an air stone is a pretty crucial step that many fish owners miss. Oxygen is essential for nitrifying bacteria proliferation, and the last will prevent ammonia from spiking in the future.

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You don’t have to buy a test kit to tell if the ammonia levels are higher than 0 ppm. While you can never say for sure, several signs should raise your suspicion.

As fish are susceptible to ammonia, they will behave in specific ways even if the ammonia hasn’t exceeded 0.25 ppm.

You may see your fish gasping for air and breathing rapidly. In severe cases, they will develop red patches, making them look like they are bleeding.

You should also check the aquarium for dead fish and plants. They will quickly rot and produce ammonia, making your aquarium smell like rotten eggs.