Why do Guppies Make Bubbles?

All fish will make bubbles since this is a perk of living in an aquatic environment. However, sometimes, the bubbles will seem larger and more frequent and may pair with awkward behavior that your fish didn’t display up to that point. That’s when you know something is different.

If you’ve had guppies for a long time and they’ve never made bubbles before, the phenomenon might alarm you, and it should. Guppies don’t do that without a good reason.

6 Reasons Guppies Blow Bubbles

In this article, we will look into the potential reasons for guppies blowing bubbles so you can identify the problem triggering this behavior.

1. Low Oxygen Level

You need to remember that the aquarium is an enclosed and tight environment where natural processes are limited. The water cannot oxygenate itself like in the wild. Lacking a filter and ignoring the need for regular water changes can lower oxygen levels, creating significant and visible discomfort for your fish.

Your guppies will display specific behavior when oxygen levels drop below acceptable parameters. Some of the symptoms relating to low levels of oxygen include:

  • Frantic gill movement – Like all other fish, Guppies use their gills for breathing. If the oxygen level drops, they tend to move their gills faster in an attempt to force more water through them. This will allow them to force more oxygen into their system.
  • Less swimming – All fish tend to swim less vigorously when dealing with low levels of oxygen. Your guppies may show low levels of energy and even apathy occasionally. However, you need to corroborate this symptom with others to eliminate other potential causes like disease, ammonia poisoning, parasites, etc.
  • Breathing near the surface – You can also see your guppies swimming near the water’s surface, opening and closing their mouths rapidly. This behavior also suggests low levels of oxygen as guppies struggle to breathe.

If your guppies display these signs, you need to investigate the situation. Perform a water change and clean fish waste and food residues to see if the situation returns to normal. To prevent this problem, regular water changes are imperative and have a good filtering system in place.

2. Poor Water Parameters

One of the most noticeable issues for guppies blowing bubbles is water quality. The water’s quality will normally deteriorate over time, which is why you need to perform regular tank maintenance to reverse the process. By ‘poor water quality, I mean higher-than-normal levels of nitrates along with dangerous levels of ammonia and nitrites. These are usually the result of dirty tank water caused by the accumulation of fish waste, food residues, and dead matter.

Ammonia poison will also arrive with other symptoms, like blood-red gills, infections, increased mucous production, and darkened body colors.

The water’s temperature and pH can also cause guppies distress. Too high or too low water temperatures will cause guppies to display their distress via bubbles and specific behavioral changes.

Keep your guppies’ environmental temperature stable to prevent health problems along the way. If the tank’s room has fluctuating temperatures, use a heating system to keep the guppies’ habitat stable.

You can control ammonia via a potent filtering system and perform weekly water changes to remove harmful chemicals. Some preventive measures also include avoiding overfeeding and overcrowding, which are 2 of the most widespread causes of dangerous ammonia buildup.

3. Overcrowded Tank

Overcrowding is a common problem with people who look to cram too many fish into a too-small tank. The problems that may arise with overcrowding include:

  • Fish stress – Many fish will display signs of stress when overcrowded. That’s because all fish need space to feel comfortable and different species have different space requirements. When crowded, your fish may experience distress, lack appetite, and display agitation.
  • Increased aggression – All fish have territorial behavior, especially males. This behavior will become more visible when overcrowded, as the fish will grow aggressive towards other tank inhabitants. This can lead to bullying, chasing, and fin nipping, often causing injuries and even death.
  • Elevated ammonia – Overcrowding leads to more fish waste which, when combined with poor tank maintenance, results in elevated levels of ammonia and nitrites. And we’ve already discussed the dangers associated with high levels of ammonia.

To avoid this issue, provide every fish with optimal living space. How much space every fish requires depends on the species. Guppies, for instance, need approximately 2 gallons of water per fish, a Betta fish needs around 2.5-3 gallons, while an Oscar needs 50 gallons.

4. Too Many Plants

Live plants are a necessity in every tank. They improve the tank’s esthetics, provide fish with hiding and comfort zones, and, most importantly, boost the water’s oxygenation. However, having too many plants in your tank can spell trouble.

Plants create oxygen during the day via photosynthesis. The problem is that plants will consume oxygen and create carbon dioxide in the absence of light, aka during nighttime. If your tank contains too many live plants, your fish may experience low levels of oxygen during nighttime.

You will see them gasping for air at the water’s surface at night, at which point you need to consider removing some of the plants. Keep enough to make your fish comfortable, but don’t add too much that you end up suffocating the environment and your fish with it.

5. Feeding on Water Surface

Fish who feed at the water surface tend to blow a lot of bubbles in the process. It’s a natural behavior that will become even more visible the more fish you have. Some fish species show a more voracious appetite, causing them to fight for food and eat in a hurry.

All this commotion and food gulping will create a lot of bubbles as a result of frantic competition for food. This mostly happens in community tanks, where different fish species will compete over food and create turbulences at the water’s surface.

6. Use of Medication

You sometimes need to use medication to treat various diseases and parasites, which can backfire in certain situations. Some types of medication and chemicals will attach to oxygen molecules, rendering them unfit for breathing.

This may cause your fish to experience an oxygen-deprived environment, leading to more bubbles and gasping for air. You should always speak to a fish professional before using any medication or anti-parasitic chemical in your main tank.

Do Guppies Make Bubble Nests?

No, they don’t. Fish that create bubble nests are called aphrophils, and guppies don’t belong to this category. Bettas and Gouramies are 2 fish species that create bubble nests. But what exactly are these?

Male fish will typically create bubble nests using oxygen, saliva, and surrounding plants, keeping the nests together. These bubble nests serve as protection formations for fish eggs which the female or male will guard until hatching.

The larger the male is, the larger and thicker the bubble nest.

Bubble nests are signs that your fish are happy and comfortable, getting ready for breeding. The problem arises if you have no aphrophils in your tank. This means that the bubble nest effect comes from somewhere else, like lacking an effective filtering system.

Guppy-only tanks, for instance, shouldn’t display any bubble nests. If you spot similar structures floating on the water’s surface, investigate the cause. Check your filtering system, consider that the snails may be responsible (if you have any), and inspect the plants for dead and decaying matter.


Guppies can make bubbles for a variety of reasons, some of which are more dangerous than others. If you spot your guppies blowing abnormal amounts of bubbles, assess their behavior and look for other signs that may reveal the cause.

avatar Noah
I’m Noah, chief editor at VIVO Pets and the proud owner of a playful, energetic husky (Max). I’ve been a volunteer at Rex Animal Rescue for over 2 years. I love learning and writing about different animals that can be kept as pets. read more...

Leave a Comment

Your email address will not be published. Required fields are marked *