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11 Reasons Why Betta Fish Stay By The Filter?

11 Reasons Why Betta Fish Stay By The Filter?

If you have already equipped their aquarium with lots of hiding spots, and despite that fact, something may be wrong if your betta is hiding behind the filter. Being a responsible owner, whether it is an environmental factor or an underlying health issue, you should find out what is causing them to do so. 

Many aquarists have experienced their fish hanging around the filter for various reasons. For new aquarists, it is often associated with illness. In reality, this is not a correct concept all the time. Bettas are known to be opportunistic feeders, so they usually try to find food around corners also. 

Why Does My Betta Fish Stay By The Filter? To forage food, your betta could be hanging around filters for a prolonged period. Other than this, many other reasons like stress or pregnancy also lead them to hide around the filter. Sickness, poor water quality, and water change can make them hide around filters. 

Whatever the reason, continue reading to learn more about why your betta is hiding behind the filter, how to stop them from doing that, and what the expected betta behavior should be. 

11 Reasons Why Does My Betta Fish Stay By The Filter?

Why Does My Betta Fish Stay By The Filter

#1. Betta Hides Behind Filters When Your Water Quality Is Poor. 

If your bettas are excessively hiding behind the filter for a prolonged period, you should use an aquarium water test kit to check the water parameter in their tank. As betta needs dissolved oxygen from the water to breathe, water perimeters and filtration systems should be working and maintained. 

Sometimes increasing the quantity of dissolved oxygen also cures your betta’s behavior of hiding behind the filter. When your aquarium is dirty, much of the oxygen the filter system produces usually escapes through the water surfaces.

This increases the gaseous exchange also. When oxygen escapes, the region adjacent to the filter has plenty of oxygen for your bettas. Thus, it can be why your betta fish stay by the filter. 

#2. It Indicates Your Tank Is Overcrowded. 

In the wild, bettas are not restricted to limited areas. So, overcrowding your aquarium can also result in excessive stress and bullying, which might cause your bettas to hide behind the filter. 

If the aquarium is overcrowded, it’s common for the vulnerable bettas to stay by the filter. Additionally, when fish are packed, some species turn aggressive and stress out their tankmates. Vulnerable bettas are likely to take shelter behind the filter or hiding spots.

#3 To Forage Food

It is common for bettas to hang around the filter and aquarium corners to find some extra food. They are usually opportunistic feeders and always look to find some algae or microorganisms to eat. This is a widespread behavior in bettas and other predatory fishes. 

As some algae get stuck to the filter’s skin of your aquarium, some bettas are likely to come to eat those algae. They might also eat microorganisms. Usually, fish that are vulnerable to dominant ones or the weaker ones than others usually come to a nearby filter to find food. 

Other than this, it can also be because you are not providing enough food to keep their appetite full. Some bettas are not enough to fight with their companion to grab more food when you are serving/dusting. 

Therefore, weaker ones may try to find a peaceful area where they can eat and find other food sources. The filter’s back is one such friendly place for bettas in every aquarium.

#4. When Betta Is Injured, Sick, Or Unhealthy, They hide More Behind The Filter.

In the wild, when bettas are likely to be preyed upon, the first thing they do is to hide their misery. Additionally, when they are injured or sick, they conceal it because this is when they are most vulnerable to being preyed upon. 

This behavior is also reflected in pet bettas living in an aquarium. Therefore, taking a deep look at your betta is recommended as soon as it comes out. Check if there is any damage or injury. 

Your bettas are likely to appear unwell or discolored, in addition to being injured. If your betta is sick, take it out to your nearest vet. Fatigue and not eating are two frequent sickness symptoms in bettas.

#5. Pregnant Bettas Stay By The Filter When They’re On The Verge Of Giving Birth. 

It is possible that some of your bettas are pregnant and trying to hide behind the filter. The sense of vulnerability or continuous bullying by tank mates may result in a pregnant one staying by the filter. 

It is pretty natural for pregnant bettas to spend more time waiting by the filter or hiding. A pregnant betta mite also hangs around aquarium plant hiding spots and decorations to investigate. 

If you notice your betta hanging around plants decoration and filters, she is likely to be on the verge of giving birth. Therefore, your fish is seeking a comfortable spot to give birth. If she cannot find a place, your bettas may opt to hide behind the filter in a tank because of the filter area’s improved water quality. If your pregnant betta stays by the filter side, she is only one or two days away from giving birth.

#6. Bullied Or Stressed Bettas Stay By The Filter. 

If you notice specific betta hiding, staying, or hanging around your aquarium’s filter, you should check the other tank mate’s behavior. Keeping peaceful bettas with an aggressive fish species like convict cichlid is never recommended because there is a high chance of temperate betta species being bullied and trying to find the safest spot in the tank. 

If you keep your bettas with species like convict cichlid, it may result in the vulnerable being better to hide or stay by the filter because they will have to find a way to live & survive. If there’s any behavior in your betta or specific fish, you should know they are very stressed.

#7. New Betta Hides Behind Filters In His New Environment Until He Feels Secure.

If you have just bought your bettas and introduced him to a new tank, he may spend the whole day hiding behind decorations or filters, if there is none, until he feels secure. If your bettas are unique, there is nothing to be concerned about because it is pretty frequent with most fish. 

Unfortunately, there is no remedy to this, but you can have them feel more at ease by adding plants, hiding spots & decorations. If you can turn off the tank’s light, it will also help them feel comfortable and relaxed. Make sure that your new bettas are not being disturbed for a bit until they appear to be expected. 

#8. Bettas Hide Behind Filters When Kept In Communal Tank or Tank That Lack Hiding Spots. 

If you have a communal tank or overcrowded fish, hiding places may not be enough for all of them. Therefore, if your collaborative tank lacks adequate hiding spots, some will look for shelter places, including filters. Unfortunately, this can be a serious problem if your communal tank has some aggressive species. 

The fish that hide for a prolonged period behind the filter or stay by the filter suffer from colossal stress and health loss. In a communal tank, if more bettas stay by the filter, it can suck up some of your fish’s fins, causing them to get stuck. 

Small bettas will likely get pulled into the input if the filter is overly powerful. If you want to prevent this problem from happening, I would advise you to decorate your aquarium with ample hiding spots to keep them safe, comfortable, and away from the filter.

#9. Betta Hides Behind Filters In Tanks With High-Intensity Light. 

If your aquarium is equipped with high-intensity light, your bettas may not appreciate it. Some fishes like darkness in nature and become active when the aquarium lights Are off. Therefore, if your betta doesn’t like high-intensity light, it may stay by the filter.

 Besides this, high-intensity light may also increase the water temperature, and betta usually likes cold water. As your betta will have some darkness beneath your tank filter, it stays by. Always install a fluorescent light or one that is dimmer in case of a freshwater fish tank.

#10. Bettas Stay By Filter Because High Water Current Provides More Oxygen. 

All bettas love to stay at a high water current because stagnant water usually has a limited amount of oxygen. So, it is normal for bettas to hang around the filter a few times a day to enjoy more oxygen.

 High water flow penetrates more oxygen and the concentration of dissolved oxygen. Water agitation will increase in the filter area; it has more oxygen. As bettas breathe with the help of gills, they usually look to find more oxygen around the filter. This is only common if you have a large aquarium. Small and medium-sized aquariums rarely experience this situation.

#11. Environmental Problems Make Bettas Stay By The Filter.

If your betta fish aquarium is not engaging, it can increase the stimulus level needed to keep them happy. A bored betta is likely to stay by the filter. Adding varieties of toys, decorations, and plants will keep your fish engaged and receive a high stimulus. 

Besides this, you can get a couple of tankmates for your betta’s company. Some bettas are typically happier in companionship than certain species with a reputation for being hosted. A bored betta is likely to be miserable and hide by the filter.

What To Do?

  1. Check the water parameter and address them adequately to keep them from hiding behind the filter. 
  2. Look for signs of sickness or injury. If there is, take it out to your local veterinarian. 
  3. Remove the aggressive face. Some stressed out and bullied betta hide behind filters. 
  4. Consider adding lots of toys, plants, and decorations that can provide high stimulus levels. 
  5. Make sure there are enough hiding spots for each betta.
  6. Avoid making any sudden changes in their environment or surroundings. Additionally, avoid adding any new fish or introducing an aggressive one.
  7. Look for environmental concerns that might be causing your betta to stay by the filter.


In this article, I have described why your betta stays around the filter. I hope you find all the answers and possible reasons why my betta fish stay by the filter. I have tried my best and gathered all the possible causes for you with the help of thorough research. 

From my experience, your bettas may need some extra food, and that’s why they’re hanging around the filter in front of you. Other than that, an aggressive fish or a lack of hiding spots could also be the cause. 

There is nothing to be serious about unless your bettas look sick or exhibit any symptoms of health issues. I have given you 11 valid reasons why my betta fish stay by the tank, so you have other reasons to check, which I have described in this article. 

If you liked this article, please share it. Don’t forget sharing is caring. Do check our other article on betta care. See you in the next post, till then, take care and goodbye.