Why Does My Betta Fish Stay by the Filter?

Many people wonder why their betta fish stays by the filter. They may think that the betta is trying to get out of the tank, or they may think that it sees a bug and is going after it. These are not the only reasons why your betta fish might stay near the filter. Read on to find out more about this interesting phenomenon!

Why Does My Betta Fish Stay by the Filter?

Your betta fish likes to stay by the filter because there is more oxygen present than anywhere else in the tank. This is because the filter increases the flow rate, which increases the amount of oxygen in that specific area.

When they are first introduced to a new home, betta fish will explore and try out different areas of their aquariums. They might explore all over before eventually sticking with one area as their own safe space.

For many betta fish, this area is right by the filter. To be honest, I think I would sit by the filter if I was a betta fish – wouldn’t you?!

They may also sit by the filter because it’s somewhere that made the fish feel safe as a small fry, so now they return to it when they are frightened or stressed.

Whatever the reason, you shouldn’t be too worried if your betta fish is staying by the filter all of the time! As long as there aren’t any signs that he’s unwell, then everything is probably fine with the little fella.

Health Implications

Although it’s natural for a betta fish to spend some time near the filter, constant presence in that area could indicate underlying issues. This behavior could be a sign of stress, discomfort, or even health problems such as gill diseases or low oxygen levels in other parts of the tank. Chronic stress in fish can lead to weakened immune systems, making them more susceptible to diseases. Regular observation of your betta’s behavior can help spot any unusual patterns early and prevent potential health complications.

Other Betta Behaviors Around the Filter

Besides staying close to the filter, betta fish may exhibit other behaviors that are worth noting. Some bettas may appear to ‘play’ in the flow from the filter, riding the current and then swimming back to do it again. This could simply be a sign of enjoyment or stimulation. However, if your betta is constantly battling the current, this could indicate that the flow is too strong and causing undue stress. Similarly, if your betta seems to be avoiding the filter entirely, it could be a sign that the noise or current is disturbing it.

Adjusting the Aquarium Environment

To discourage bettas from spending all their time by the filter, consider making some adjustments to the aquarium environment. Start by ensuring your tank is large enough for the fish to explore and has plenty of hiding places. Plants, rocks, or betta hammocks can provide safe and appealing alternatives for your fish to hang out. You can also experiment with the filter’s placement. Putting it in a corner or less frequented area can make other parts of the tank more attractive. Additionally, consider adjusting the tank’s temperature and making sure the water is clean and well-oxygenated to make the whole environment comfortable for your betta.

Types of Filters

Different types of filters might affect your betta fish’s behavior differently. The two most commonly used filters for betta tanks are sponge filters and hang-on-back (HOB) filters. Sponge filters create gentle water movement and don’t produce strong currents, making them an excellent choice for bettas. On the other hand, HOB filters can create more current, which might attract bettas that enjoy swimming against the flow. However, if the current is too strong, it could stress the betta. Each type has its advantages and potential drawbacks, so choose the one that best suits your betta’s behavior and needs.

Comparison with Other Fish Species

Observing how betta fish behavior around filters compares to other fish species can provide valuable insights. Betta fish, being labyrinth fish, can breathe atmospheric air and often don’t need as much water movement for oxygenation compared to other fish species. Species like goldfish or tetras are more likely to swim in all parts of the tank and don’t usually hover near the filter as bettas might do. This unique behavior could be attributed to the betta’s natural habitat in slow-moving or stagnant waters, unlike other species that come from fast-moving rivers or streams.


How do you keep betta fish away from the filter?

You can keep a betta fish away by reducing the flow rate of the filter. This will make the water moves slower, and it will be less likely to make your betta fish attracted to the area.

What happens if the betta fish swims up to the filter?

If your betta fish is swimming near the filter, but not actually touching it or staying beside it all of the time, then you don’t really need to worry about this. If they are constantly trying to get closer and closer to the thing that’s moving water around without any control (and even when there aren’t any insects in sight), then reducing the flow rate might be a good idea!

Is my tank too small for a filter?

No, I wouldn’t say that – filters are designed for smaller tanks as well as larger ones! It should also depend on what type of filter you have got though… some types will work better than others depending on how big your tank is.

Will reducing the filter flow rate affect my betta fish?

It shouldn’t do, but reducing the flow rate will make it less likely for your betta to be attracted to one area of their tank.

What do high and medium water flows mean on an aquarium filter?

If you’re looking at getting a new filter, then these are descriptions given by manufacturers as guidance for what type of tanks each model will work best with. High-flow filters tend to have stronger pumps that can pump out more water, but they are also more expensive.

Medium-flow filters are usually a bit cheaper and tend to be suitable for most types of tanks. Just remember that if your betta fish is staying by the filter all of the time, then you might need one with an even less flow rate!

Can you make a betta fish go near the filter?

It’s difficult to get a betta fish used to go towards an area that they are not normally attracted to. They will be most likely happy with their own space, and it might even stress them out if you try and force them into somewhere new.

How often do betta fish need to be cleaned?

Bettas are very low maintenance, but you should clean out their tank once every two weeks. You will also want to replace the water with fresh water at least once a month. How often depends on how many fish you have in each tank!

Should the filter be kept on?

Yes, it’s very important that the filter is kept on at all times. Even when you’re not home and can’t see your betta fish, he will still be able to benefit greatly from having a good quality filter nearby.


In conclusion, your betta fish might stay by the filter for a variety of different reasons. They may be attracted to more oxygen in that area, they may remember their safe space from when they were young and small fry, or they could just think it is really cool there!

Which reason do you think your betta likes staying near the filter? Let me know in the comments below!