Betta Ammonia Poisoning (Symptoms & Treatment) is supported by our readers. When you buy through links on our site, we may earn a commission.

Betta ammonia poisoning is a silent and deadly disease that can affect your Betta, and if not caught in time, it can kill them. Typically, ammonia poisoning happens when you are setting up a new tank. But it can also happen when you add too many fish to an already established tank. 

There are several more reasons ammonia poisoning occurs, as you will see. We will go over all of them, as well as the signs you need to look out for to keep your fish healthy and safe. 

In order to prevent and fight betta fish ammonia poisoning, you will need to understand more about it. When the pH levels in your betta fish tank become elevated, this will offset the nitrogen cycle, which causes ammonia poisoning.

When water conditions are at the correct levels, there should not be any ammonia detected in the water. However, several factors can contribute to and cause ammonia levels to rise. Ammonia, even small doses can cause damage to the gills. Large amounts of ammonia can prove to be fatal to your betta fish.

Betta Fish Ammonia Poisoning Symptoms

Once your Betta starts showing symptoms of ammonia poisoning, the damaging process has begun already. Preventative maintenance is imperative to your Betta’s health. 

Gasping for Air

If you suddenly see your Betta at the top of the tank gasping for air, it may be suffering from one of the first symptoms of ammonia poisoning. The ammonia will begin to burn your Betta, which will cause it to become desperate for clean oxygen at the top of the tank. You may even find that your Betta is trying to escape your tank.

Changes in Gill Color

The most obvious sign of ammonia poisoning you will notice is when their gill starts changing color. When this occurs, you should take action immediately. 

When ammonia poisoning begins to set in, your Betta’s gills will turn purple or red in color, and they may begin to look inflamed. If action is not taken immediately and the ammonia poisoning continues, your Betta’s gills will begin to bleed. 

Inflamed Anus and Eyes

If the ammonia poisoning is not treated right away, you Betta’s sensitive areas will become inflamed. Its anus and eyes will become severely irritated and even damaged.

Red Streaks on Body and Fins

The ammonia poisoning will slowly begin to damage your beloved Betta’s body, and you may begin to notice red streaks appearing on its fins and body. 

These red streaks can sometimes be confused with the stress stripes your Betta will get when they become overly stressed. If you see the red streaks appear on your Betta, you should test the water immediately to rule out ammonia poisoning. 

Loss of Appetite

A sure sign that something is wrong is when your Betta begins to lose its appetite. Although, loss of appetite can result from various diseases, including depression and stress. 

However, if your Betta suddenly loses its appetite, you should begin investigating the possible reason. One of the first tests you should perform should be water condition testing to make sure their water is safe and healthy.


Lethargy is another sign of ammonia poisoning, although sometimes its less noticeable. If you Betta has stopped swimming or is passively floating around the bottom of the tank, you should begin investigating why this is occurring. 

Several different diseases can cause lethargy. However, testing the water conditions first will help to rule out several of those diseases because ammonia poisoning will show up immediately during the water testing.

What Causes Betta Ammonia Poisoning

Too much ammonia in the tank can lead to ammonia poisoning. Several factors can contribute to ammonia poisoning in your fish tank. Learning about these factors will help you practice preventative maintenance to keep your water conditions at healthy levels.

A New Tank That Hasn't Cycled Properly

Your fish tank is an ecosystem. When you first set up the aquarium, the ecosystem is rather sensitive. The essential bacteria needed to help break down the ammonia in your tank into less harmful compounds have not yet become fully established.

The tank’s cycling takes approximately 6 to 8 weeks for the bacteria to establish itself. During this cycle, you will most likely see ammonia spikes in the water until the bacteria have become established.

Build Up of Decaying Matter

By doing regular inspections of your tank, you will be able to spot any decaying matter that has the potential to cause ammonia poisoning. Things such as feces, rotten food, dead plants, and biological waste will cause the ammonia levels in your tank to rise, which can result in ammonia poisoning.

If you Betta is part of a community tank, then while doing your tank inspection, be sure to look for sick or dead fish. Dead fish will produce high levels of ammonia when they begin to decay.

Water Changed Infrequently

Regularly changing the water in your tank will dilute the ammonia buildup by replacing the unclean water with fresh, clean water. Smaller tanks will need to have the water changed out more often than larger tanks. Not changing the water often enough will cause ammonia poisoning in your Betta.

If your tank does not have a filter, the water will need to be changed frequently. To keep your Betta healthy, your Betta needs a filter in its tank, regardless of popular belief. The filter will help you regulate the ammonia levels.

If Bacteria Colonies Die

Every tank should have a healthy bacteria colony. This colony helps to neutralize the ammonia buildup in your tank. However, if your filter stops working properly, that bacteria colony may start dying. Treating your tank with bacteria-killing medications will also eliminate the good bacteria colony. When the bacteria colony in your tank starts dying off, the ammonia levels will increase, and ammonia poisoning will occur.

How To Treat Betta Ammonia Poisoning

Ammonia levels in your water should be at 0 parts per million (ppm). Making sure the ammonia levels are lowered to 0 ppm is the only way you will be able to treat ammonia poisoning in your Betta successfully.

Ammonia Detoxifier

Adding an ammonia detoxifier to treat your tank is the quickest solution to getting your tank back to normal. Anytime the ammonia levels rise above 0 ppm, you should use the ammonia detoxifier. 

Ammonia detoxifiers reduce the harmful levels of ammonia in your tank rather than getting rid of them altogether. The detoxifiers will reduce the negative effect of the ammonia and bring the levels down to a normal, healthy level, which will benefit the good bacteria in your tank. 

Using an ammonia remover is especially helpful when used with a new tank. We recommend the API brand from Amazon. It’s less than $10 for the bottle, and it will last you a long time.

API AMMO-LOCK Freshwater and Saltwater Aquarium...
  • Contains one (1) API AMMO-LOCK Freshwater and Saltwater Aquarium Ammonia Detoxifier 16-Ounce Bottle
  • Detoxifies ammonia in aquarium water and tap water
  • Works instantly to make aquarium water safe for fish
  • Reduction in ammonia levels measurable on any API Test Kits
  • Dose freshwater and saltwater every two days until ammonia is not detected

Add Ammonia Removal Inserts to Your Filter

One thing you can do to help prevent the buildup of harmful levels of ammonia in your tank is to add ammonia removal inserts to your current filter. As the water is filtered, the inserts will remove any traces of ammonia in the water. This will help reduce any stress your Betta may be under.

We recommend the AquaClear Ammonia Removal Inserts from Amazon. They are inexpensive, coming in at less than $10 for a three-pack.

AquaClear 30-Gallon Ammonia Remover, 3-Pack
  • Removes and controls harmful ammonia and nitrite
  • Ideal for new or heavily populated freshwater aquariums
  • Replacement media designed to fit the AquaClear 30 filter
  • Only suitable for freshwater aquariums up to 30 gallons
  • Includes three AquaClear 30 Ammonia Remover Inserts

Water Changes

You should go ahead and perform a 50% water change in your tank if you witness any of the symptoms of ammonia poisoning. If you are unable to buy any of the recommended detoxifiers or removal inserts, you should plan to perform the water change every two days until the ammonia levels are reduced to 0 ppm.

To avoid harming your Betta with temperature shock while performing the water change, you should make sure that the temperature of the new water matches that of the water to be replaced.

Do Not Overfeed Your Betta

When leftover food remains in the tank, it will contribute to ammonia levels rising. When the leftover food begins to decompose, it causes the ammonia levels in your tank to spike. 

Do not overfeed your Betta. Not only will there be leftover food, but the more your Betta eats, the more waste it will produce, which adds to the ammonia buildup. 

Only feed your Betta enough that they can eat all of it in less than two minutes and then remove any leftover foods from the tank. Bettas can go a day without food. Doing so can also reduce the possibility of your Bettas becoming constipated.

How To Prevent Ammonia Poisoning

Preventative maintenance is always better than reactive maintenance. Meaning, you should do whatever you can to prevent ammonia poisoning before it happens rather than needing to treat it after it happens. Here are suggestions for the best preventative maintenances.

Add Nitrifying Bacteria

Nitrifying bacteria can effectively prevent ammonia poisoning in fish tanks, especially the new tanks. Nitrifying bacteria will break down the ammonia and create a safe environment for your Betta. 

API has a Quick Start Nitrifying Bacteria that is highly effective and only costs $15.

API QUICK START Freshwater and Saltwater Aquarium...
  • Contains one (1) API QUICK START Freshwater and Saltwater Aquarium Nitrifying Bacteria 16-Ounce Bottle
  • Allows instant addition of fish when starting a new aquarium
  • Reduces compounds harmful to fish when used routinely
  • Helps prevent fish loss in freshwater and saltwater aquariums
  • Use when starting a new aquarium, when adding new fish and when changing water and filter media

Frequent Water Changes

One of the most beneficial tasks you can perform for your fish tank is frequent water changes. Changing out the water frequently will help to remove the old and dirty water that your filter is unable to process. Also, as we mentioned earlier, frequent water changes are an excellent way to treat ammonia poisoning. 

Water Filters

Bettas may be a tough breed, but they have basic everyday requirements that need to be met, just like any other fish. Some of those needs are a heater and water filter in their tank. Don’t believe the myth that Bettas can live in a fishbowl. They need at least a five or ten-gallon tank with a heater and a water filter. The filter will clean your Betta’s tank while removing the ammonia buildup.

Adequate Tank Size

Smaller tanks will get dirty faster. As we mentioned above, your Betta needs at least a five-gallon tank. Anything smaller than five gallons won’t be large enough, and it will be cruel. It will also cause more work for you because you will have to do more frequent water changes and cleanings.

Water conditions in smaller tanks can change rapidly. Smaller tanks are also more likely to experience faster ammonia buildup over time than larger tanks would.

Frequent Tank Cleaning

Ammonia can be produced by decaying matter in your fish tank such as rotten food, fish waste, or plants. Regular tank cleaning and vacuuming the substrate should eliminate any remaining waste from your tank.

Adding an Air stone

Air stones will help pump oxygen through your tank by creating flows of tiny bubbles that are then transported all over the tank oxygenating the water, which helps to disperse the ammonia that has begun to build up in your tank.

Air stones are not a necessary addition to your tank, but they are an inexpensive way to help keep your tank healthy. However, some Bettas don’t particularly like them. You will need to test one in your tank to see if your Bettas react positively to it. 

We recommend these inexpensive aquarium air stones from Amazon.

yueton Pack of 10 Cylinder Aquarium Bubble Air...
  • Help to keep fish healthy and adds extra beauty to the aquarium.
  • Suitable for : Fish Tank, Aquarium
  • Material : Mineral, Plastic; Color : Blue
  • Size: Approx. 0.59*1.57 inch / 1.5*4cm(D*H)
  • Suitable for inner diameter 4mm soft tube.

Buy an Ammonia Test Kit

Once again, preventative maintenance can save you headaches later, as well as keep your fish healthy and safe. An ammonia test kit is a great way to keep track of the level of ammonia in your tank. With regular testing, you’ll know right away if the ammonia levels have begun to rise, and you can act accordingly to reduce the levels safely. 

We recommend the API Master Test Kits sold on Amazon. These kits will allow you to check the ammonia levels in your tank as well as checking the pH levels, nitrates, and nitrites. 

  • Contains one (1) API FRESHWATER MASTER TEST KIT 800-Test Freshwater Aquarium Water Master Test Kit,...
  • Helps monitor water quality and prevent invisible water problems that can be harmful to fish and cause...
  • Accurately monitors 5 most vital water parameters levels in freshwater aquariums: pH, high range pH,...
  • Designed for use in freshwater aquariums only
  • Use for weekly monitoring and when water or fish problems appear


Preventative maintenance is key in keeping your Bettas safe and healthy. Make sure you are doing your part by maintaining the tank, keeping it clean, and performing regular water testing and changes. 

We hope this article has given you everything you need to keep your Bettas safe from ammonia poisoning. 

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Michele Taylor
Michele Taylor

Hello, fellow aquarists! My name is Michele Taylor, and I am a homeschool mother of six children, which includes five boys and one girl. My kids range in age from five-years-old to eighteen-years-old.

Growing up, our family had a large aquarium with angelfish, goldfish, and lots of different varieties of neons. We also had a “suckerfish” that grew to be about six inches long.

1 thought on “Betta Ammonia Poisoning (Symptoms & Treatment)”

  1. It looked as if my filter broke and dumped all the charcoal in the tank so he got very poisoned. I have for 3 wks done all I can, he is a fighter. I put him in a recovery tank, used betta fix and betta water conditioning. I excercise him 2x a day to get him to move for a minute or 2 and eat a few bites. Then he just lies down or holds to the filter. Since he is such a fighter I don’t want to give up. Is there anything else I can do? I have a small filter going thats gentle, he didn’t like the airstone, he has live plants from petsmart, and I’m changing the small tank every 3 days (temporary tank is small}. Thanks for any advice


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