Why is my Goldfish Blowing Bubbles? (With 5 Quick Solutions)

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As a fish owner, I’ve been growing goldfish for years. Over time, I learned how to identify signals that indicate that something had gone wrong. One example would be a goldfish that is continuously blowing bubbles. To make sure the condition will get solved in your tank, I decided to point out all the possible reasons and solutions for the phenomenon.

Goldfish typically blow bubbles due to respiratory distress, secondary to high ammonia, nitrates, and nitrites levels. However, goldfish may also produce bubbles as they empty their swim bladder. That allows them to sink to the bottom when aggressive tankmates frequent the upper sections.

As we proceed in this article, I will share a few other reasons that may consistently force your goldfish to blow bubbles. I will also show you what steps you should take to make sure your fish won’t suffer from unnecessary distress.

Why does my Goldfish Blow Bubbles?

Goldfish are not like bettas and do not have a reputation for creating nests of bubbles for mating and breeding purposes.[1] As such, if you see your goldfish blowing bubbles, you should make every effort possible to identify the potential reasons. 

These typically include:

1. Rapid Breathing

Fish breathe through their gills, organs that extract oxygen from the water. That oxygen is eventually absorbed into the bloodstream. However, fish also use their mouths for breathing. They usually suck and spit water to eventually pass it over their gills, allowing the organs to extract oxygen more efficiently.

However, when a goldfish opens its mouth, air may escape, creating a pocket and forming bubbles.[2] To the outside eye, the goldfish will look like it is blowing bubbles. If the fish’s breathing is rapid and labored, you will notice more and more bubble extractions.

2. Active Swim Bladder

The swim bladder is an organ that fish use to control their buoyancy. The swim bladder is so vital that, when its functions are compromised by injury or disease, the fish loses its ability to swim correctly. For example, it may force the creature to lie on the bottom of the tank.

Bubbles can sometimes play a role in the operations of the swim bladder. That is to say; a goldfish can rise by allowing gasses to fill the swim bladder.[3] That allows the fish to swim to the top while exerting little to no energy.

The reverse is also true. Your goldfish can quickly sink by allowing gasses to escape the swim bladder. When that happens, the goldfish becomes heavier and forced to move downwards. Fish can achieve this result by burping to release air, leading to the production of bubbles.

If your goldfish has reasons to swim towards the bottom, you will naturally see more bubbles coming out. For example, if there are aggressive tankmates at the top or middle section, your goldfish will seek safer locations.

3. Supersaturated Gasses

Fish need oxygen in their water to survive. However, high concentrations of oxygen are harmful and could suffocate your goldfish. Supersaturated gasses introduced to a tank via pressured tap water can cluster under the skin, making the fish look like it has a tumor.

The presence of supersaturated gases can cause gasping at the surface and blow bubbles, not to mention bulging eyes.[4] On occasion, the bubbles will escape from the fish through the gills. 

The severity of the disease depends on how much oxygen has dissolved, and the involved organs. More factors contributing to that disease in aquariums include leaking air pumps or valve systems.[5]

4. Air Pumps & Airstones

Air pumps produce bubbles. Goldfish are drawn to these bubbles, and if you observe the fish closely, you will see them nibbling at the tiny air pockets.[6] Sometimes a goldfish even swallows the air in these bubbles.

This air is eventually pushed out of the goldfish’s body through the mouth or gills as bubbles in the best-case scenario. In the worst-case scenario, the air eventually compromises the operations of the swim bladder.

Either way, if your aquarium features many air pumps or air stones, the source for the bubbles could be in your devices. You will see the goldfish spitting those, but that only happens because the fish had stored it in its body.

5. Low Water Quality

If your goldfish is blowing bubbles at the top of the tank, you have every reason to worry. It means that the quality of the water in your aquarium has deteriorated significantly. If the water came from a tap, you should perform a test to determine the amount of chlorine and chloramine in the tank.[7]

You could quickly test your water using testing stripes, such as the Tetra EasyStrips 6-in-1 (link to Amazon). These will test your water for chlorine, nitrites, nitrates, pH, and hardness. I also recommend the API Aquarium Test Kit (link to Amazon). That bundle is a bit more expensive, although it lasts much longer.

These substances are toxic to fish. Some aquarists believe that they can bubble chlorine out of the water. They are right; however, that doesn’t apply to chloramine. Goldfish that are living in tanks with toxins will rush to the surface in search of an escape.

If chlorine isn’t at fault, I suggest testing for ammonia. Ammonia will gradually burn your goldfish’s gills, affecting its ability to breathe. The bubbles you notice signal that the fish is gasping for air and is in respiratory distress.

Ammonia is common in small, overstocked tanks. Goldfish are quite active and messy creatures. Therefore, if you keep too many of them in a too-small tank, the ammonia concentration will spike, endangering their lives.

If ammonia isn’t the issue, then your tank is simply oxygen deficient. That can happen as a result of overstocking, overcrowding, and high temperatures. It can also happen in tanks with stagnant water.

Your goldfish will run to the top where they will produce bubbles as they gasp for air because the water at the top has more oxygen than the water at the bottom. You are also likely to see that sort of behavior in other fish in your tank.

How to Treat Goldfish that Consistently Blow Bubbles?

If your goldfish blows bubbles occasionally, you don’t have to concern yourself with its behavior. Nevertheless, if the bubbles have become a consistent phenomenon, you can use the following steps to fight them:

1. Improving Water Quality

If the water quality is to blame for the bubbles, you should take steps to improve the conditions in your fish tank. That means ensuring that your goldfish has a pH ranging from 7.0 to 8.4 and a temperature ranging from 60 to 74 degrees F.[8]

If you’ve noticed that the pH is lower than 7.0 (after using a testing kit), you should perform more frequent water changes. Start by replacing 15-20% of the water each week. Try conducting gradual changes since abrupt fluctuations in pH could do more harm than good.

However, if your goldfish is blowing bubbles at the surface now, you don’t have to wait a week. At this point, it would be best to perform a partial water change immediately to improve the conditions in the tank, giving the fish the relief it requires.

Also, the tank should be at least 20 gallons in size to prevent overcrowding. The more goldfish you have, the bigger the tank should be. I also suggest eliminating a few plants and decorations, allowing your goldfish to swim more freely.

2. Taking Care of Toxins

If your water came from a tap, I suggest using a Dechlorinator. Dechlorinators are not that difficult to find and are relatively cheap. I personally use the API TAP Water Conditioner (link to Amazon). That product prevents tap water chemicals from causing gill distraction by neutralizing chlorine and other chemicals. 

The same goes for products that actively remove chloramine. However, some people prefer to use reverse osmosis units. You can save some time by filtering the tap water with high-quality carbon before adding it to the tank.[9]

If ammonia is responsible for the bubbling, your only option is to perform a water change. There is no way to prevent ammonia from accumulating since fish naturally extract it through their urine and gills. Nevertheless, the aquarist’s mission is to control the accumulation rate. 

You can prevent ammonia from becoming an issue in the future by adding a more powerful filter. But it would help if you also remembered to clean your current filter’s elements. It won’t do you any good if the parts are clogged.

I also recommend eliminating organic contaminants in the water, such as leftovers, waste in the substrate, and dead plants and animals that produce ammonia when they rot. You can achieve that by vacuuming your substrate once you clean your aquarium.

3. Oxygenating Your Tank

A powerful filter can create the agitation required to increase the diffusion of oxygen in an oxygen-deficient tank. However, a more practical option involves adding air pumps, air stones, and bubblers.

These devices will increase the oxygen content in the tank pretty quickly. For that, I highly recommend the 10 Pieces Cylinder Bubble Diffuser Airstones (link to Amazon). That highly affordable bundle contains ten air stones which you can quickly scatter across your tank.

It would be best if you also considered adding natural plants to your goldfish’s aquatic environment. They consume carbon dioxide while generating oxygen. Although you should bear in mind that the process reverses during the day. So, try to minimize light exposure.

4. Supersaturated Gasses

If your fish is blowing bubbles because of supersaturated gasses, you can resolve the issue by agitating the water. By creating movement, you will be able to release trapped gas that had dissolved to the water. 

Do this before you add the water to the aquarium, especially if you’ve poured the water into a container from a relatively high water source. You can achieve similar results using an air pump, but make sure that the process is performed outside your fish tank.

5. Eliminating Aggressive Tankmates

As was mentioned above, aggressive companions might derive your goldfish to the bottom of the tank. Although to sink correctly, your goldfish will have to extract air from its swim bladder, producing bubbles in the process.

That is the proper functioning of the swim bladder. Nevertheless, those bubbles indicate that your goldfish is bullied and possibly suffers from distress. To solve that, I suggest taking out aggressive tankmates that consistently chase your goldfish.

Those companions vary in each tank. Your best choice would be to observe the tank and determine if some fish are bullying your goldfish. Try to see if chases are going on or if your goldfish features some nipped fins. If so, take out the problematic fish.

If you found this article useful, here are a few related ones that may also interest you:


If your goldfish is blowing bubbles, it could merely be its way to oxygenate its gills. Although, things should catch your attention if your fish does it repeatedly and consistently. That could indicate that the water quality has deteriorated.

Start by testing your fundamental water elements, including chlorine, ammonia, nitrates, nitrites, and pH. You can do that by getting a few testing stripes. If the water is inappropriate for fish, you should conduct more frequent water changes. 

That is particularly true if the pH is below 7.0, or if the ammonia levels are relatively high. You should also make sure that the tank doesn’t feature aggressive tankmates that consistently bully your goldfish. If it does, take them out or consider placing a divider.


  1. https://animals.mom.com/happens-fish-lay-bubbles-top-water-8583.html
  2. https://www.reference.com/pets-animals/goldfish-blow-bubbles-4de7416ce3f9fab9
  3. http://www.madsci.org/posts/archives/2008-04/1208215528.Zo.r.html
  4. http://goldfishbubbledisease.blogspot.com/
  5. https://en.wikivet.net/Gas_Bubble_Disease
  6. https://goldfish-emergency.com/goldfish-blowing-bubbles/
  7. https://www.petplace.com/article/fish/pet-care/small-pet-care/fish/bubbles-fish-tank-mean/
  8. https://www.aqueon.com/information/care-sheets/goldfish
  9. https://www.thesprucepets.com/remove-chloramines-from-tap-water-2924183