Why is My Aquarium Filter Making Bubbles?

Why is My Aquarium Filter Making Bubbles?

The formation of bubbles in a fish tank is necessary to supply sufficient oxygen to the fish and plants. While, in some cases, the aquarium filter starts to make bubbles excessively, and it is not a good sign. 

Why is My Aquarium Filter Making Bubbles? Usually, the aquarium filter makes abundant bubbles due to improper filtration, excessive dirt, and residues in its media. You will also observe excessive bubbles from the filter when it is old and starts to break. Additives or medications in the tank and splashing water on the surface from the filter outlet are other reasons.

Some amount of bubbles, an air-driven filter form that does not stay for a longer time and burst immediately are normal.

The problem arises when these bubbles do not pop and remain in and on the water surface.

Filters have several benefits in the fish tank, and you must ensure their proper working and performance. 

Why is My Aquarium Filter Making Bubbles?

More than usual amount and colored bubbles are the indicator of non-functioning filter: It threatens the aquatic life inside the tank.

They spread and float all over the surface and cover it completely: you will also observe them on the sides.

They are smaller in size that spread in the water: They also rest on different objects like decorations and plants, causing the disturbance.

Air pump issue

When a problem occurs in the air pump of the fish tank, the filter is also affected because air-driven filters operate with a pump.

Usually, the diaphragm wears or damages the pump that allows air to pass through the system.

The impeller that is not in good condition due to clogging or any other issue causes the filter to produce more bubbles.

Disturbance on the water surface

The water surface disturbs when the water comes from the outlet splash on the surface, forcing air into the water.

It occurs when you hang the filter higher than the water level, and the distance between pouring water and the surface increases.

Inappropriate cleaning products

Cleaning the filter is essential to keep the tank environment clean and healthy. However, choosing the wrong cleaning agent can cause a lot of problems.

The soap may remain in the inner or narrow parts of the system if you do not rinse them with plenty of water.

This soap will form a bubble when the tank water runs through it, releasing bubbles into the aquarium.

Moreover, the soap may harm the fish and plants in the tank as it contains many chemicals.

Improper filtration

If the filtration process of the filter disturbs an aquarium due to any reason, it can result in unnecessary bubbles.

It may occur due to the deposition of wastes on water tubes, any stuck solid particles in the intake tube, or fish wastes in any part of the equipment.

Rinse and washing the filter body is not enough; you should clean every tube, piping, and compartment of it.

The high amount of nitrogenous wastes in the aquarium

As the aquarium is a living aquatic space and the fish produce wastes that contain nitrogenous components.

This bioload, uneaten food, decaying plants, and other substrates in the tank collectively fuse and deposit in the filter.

They use to jam infiltration systems, causing the blockage in different parts, resulting in unusual bubble production.

Dirty filter media

Filter media such as sponges or pads get dirty with time and use and become the cause of this issue.

They perform the function of restricting wastes, residues, and other unnecessary components to enter the filter.

This constant contact with solid waste components clogs the media by preventing air and water pass through smoothly.

The water and air will start to move through the unclogged part, and the pressure increases, resulting in a disturbed flow.

Damaged or old filter

Any damaged or broken part of the filter will affect its functioning, resulting in poor performance.

Sometimes, the old filter starts to make a bubble, and you remain unaware of the broken components inside it. 

 Other sources of bubbles in a fish tank

Bubbles do not form only because of the filter; there are also other causes of bubbles inside the fish tank.

Do not confuse with the reasons and try to inspect all equipment and objects in the aquarium.

Betta bubble nest

Sometimes, you will see a nest of small, abundant bubbles forms in your betta tank in the corner and between many floating plants.

Usually, betta fish form the nest at the time of spawning and protect them until they hatch.

The male betta builds this nest using the mucous in its saliva and sticks together at the surface or corner of the fish tank.

Gourami and some other fish also do this at the time of breeding and spawning.

Water change and temperature

Water change is necessary, but when you change a large volume of water at once from a running fish tank, it can lead to bubbles formation.

The water parameters like temperature fluctuation is also a reason, which occurs by adding hot and cold temperature into the tank.

Additives in water


Also, these additives increase the viscosity of water, making it thick, which allows the bubbles to stay longer.

Pearling of plants

Plants produce oxygen at daytime which is beneficial for a tank, but when the amount of oxygen increases to a greater extent, they form bubbles.

Also, algae, if present, produce more oxygen that overall increases saturation.

It becomes normal when the saturation level decreases at night as the plants consume oxygen.


When you start to overfeed animals in the tank, the leftover and residues begin to deposit in the fish tank.

Also, if the fish feeds more, it produces more wastes, leading to more problems.

Oil film on the surface of the water

Sometimes, oily bubbles form on the water surface because of the thick biofilm and oil layer that traps the air.

It happens when you feed oiling substances to your fish that release oil deposits on the top surface.

Moreover, your hands may be a source of oil in the water when to put them uncleaned and unwashed in the aquarium. 

This oil slick also results in blocking gas exchange leading to a decrease in oxygen levels.

Should my aquarium filter make bubbles?

Small bubbles by the filter are normal as it happens what water and air move through the filtration unit with force.

These bubbles, after reaching the top surface, dissipate, releasing fresh oxygen for the inhabitants. 

They are a sign of a better filtration process, considering mechanical and biological aspects.

Do these bubbles oxygenate water?

Yes, the bubbles have air and can serve oxygen to the fish, but to a limited extent.

If they do not burst, the oxygen will not dissolve in the water, and the oxygenation level remains low.

Therefore, they must pop quickly unless they act as a barrier for the inhabitants instead of being beneficial.

Is excessive bubbles formation harmful to aquarium fish?

When their amount increases extensively, they look like a foamy layer covering the whole surface and can make the water cloudy by stirring up the sediments lying below.

These disturb the view of your tank aesthetic and make it difficult for fish to see and swim properly.

How do I get rid of bubbles in my fish tank?

You can eliminate the issue by following simple methods.

Surface agitation helps to dissipate the thick oil or biofilm on the water surface the capture bubbles.

Deep cleaning of every corner, wall, object, and equipment of the fish tank will help you remove algae wastes, debris, wastes, and scrapes.

Add food into the tank in the amount that your fish can eat to avoid leaving uneaten food pieces.

Regular water change is the key to avoid unnecessary issues and other problems.

Keep an eye on water parameters, particularly the temperature, and avoid frequent temperature changes.

Gather knowledge and information as much as possible before establishing your aquarium. Examine all parts of the filter and wash them frequently.

A protein skimmer is the easiest way to remove excess nitrogenous wastes.

Never use soap or foaming agents to clean any equipment or decorations of the aquarium.

Level up the water surface to reduce surface tension

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