Do Goldfish Need a Filter?

Most people who have kept a goldfish know that they require a filter in their tank. This is because goldfish produce a large amount of fish waste and a filter helps to keep the water clean.

However, some people believe that goldfish do not need a filter and can be kept healthy without one. So, what is the truth? Do goldfish need a filter? Here we answer all your questions so you can be confident about caring for your goldfish!

Do Goldfish Need a Filter?

goldfish need tank

The bottom line regarding goldfish is that they don’t need a water filter but should have one. Most people believe that goldfish need a filter in their tank, and this is because filters help to keep the tank water clean and free of toxins.

However, goldfish are quite hardy fish and can live without a filter. They can do this because they have a unique organ which makes them less reliant on the high oxygen content in the water. Therefore, as long as there is some minor form of aeration in their tank, goldfish will be able to survive.

Of course, this doesn’t mean you can neglect your goldfish tank altogether. Goldfish still produce waste, and the tank will need to be cleaned regularly. There will also be an accumulation of uneaten food. However, if you don’t have a filter yet, don’t worry, as you’ll still be able to keep your fish alive.

But while it is possible to keep a goldfish without a filter, it doesn’t mean you should. A filter for your goldfish tank helps to remove waste from the water and keeps the water clean. In addition, filters provide oxygenation for the water, which is essential for goldfish.

This is especially important in a small tank or for a goldfish in a bowl. In such environments, poor water quality is common as goldfish are such messy fish. Partly due to this, fish bowls aren’t a good idea for goldfish as they need at least 20-gallon fish tanks.

Read our guide on how to filter fish bowls.

Imagine being in a room full of cigarette smoke. Just because you can live in it, it doesn’t mean that you should. Likewise, goldfish will live a happier and healthier life with a filter than without one.

Do Goldfish Need an Air Pump?

Many filters will come with a way to aerate the water, but some don’t. So if a goldfish can technically live without a filter, can it also survive without anything disturbing the water?

Goldfish live naturally in water that is low in dissolved oxygen. As a result, they can adapt to a wide range of environmental conditions. In fact, goldfish have been known to survive in everything from ponds to toilets.

However, when it comes to providing a long and healthy life for your goldfish, an air pump (or air stone) is always a good idea if your filter doesn’t disturb the water. Without any aeration, water can become stagnant, and oxygen levels will gradually fall.

An air pump helps circulate the water and keep dissolved oxygen levels high, making breathing easier for your goldfish. In addition, an air pump can also help to prevent the build-up of harmful toxins in the water.

As a result, aeration is an integral part of any goldfish tank. If you’re deciding between a filter or air pump, then you often don’t need both. If you have a filter that disturbs the water, then it’ll be doing the same job as an air pump.

If you’re a little bit confused about how some air can increase the oxygen in water, it’s essential to learn about the gas exchange in fish keeping.

What Is Gas Exchange In a Fishtank?

Maintaining a healthy fish tank requires more than just keeping the water clean. It is also vital to ensure that the water has the correct levels of oxygen and carbon dioxide.

This process, known as gas exchange, is essential for the health of both fish and plants. Oxygen enters the water through surface agitation, such as from a filter or bubbler.

On the other hand, carbon dioxide is produced by the fish themselves and can build up to harmful levels if not properly removed.

Gas exchange ensures that both oxygen and carbon dioxide are continually replenished, providing a healthy environment for all aquarium inhabitants.

Agitating the water allows for more oxygen from the air to be dissolved and for excessive carbon dioxide in the water to be released.

Without this agitation, oxygen can only reach the stagnant water molecules at the surface. Goldfish can be great pond fish, but whether it’s tap water or natural water, high oxygenation with a solid nitrogen cycle is important.

How Do Goldfish Get their Oxygen?

All fish need oxygen to live, and goldfish are no exception. However, goldfish are unique in the way that they breathe. Most fish have gills that allow them to extract oxygen from the water around them.

Goldfish, on the other hand, have a special organ called the labyrinth that helps them to breathe air. The labyrinth is located near the goldfish’s kidney and allows the fish to take in their oxygen supply from the air.

This evolutionary adaptation from their natural habitat allows goldfish to survive in bodies of water with low oxygen levels. It can also allow them to survive for up to an hour out of water. While they are amazingly resilient creatures, they’ll still benefit from the healthiest environment possible.

How To Ensure High-quality Water for Your Goldfish?

high quality water for goldfish

Fish keepers know that providing their aquarium fish with high-quality food and water is essential to keep fish healthy.

When it comes to water, there are a few things that you can do to ensure that your goldfish have the best possible quality. First, it is important to use a filter and air pump to remove any impurities from the water and keep circulating oxygen.

Second, you should regularly change the dirty fish water to remove the waste that settles at the bottom of the tank and your aquatic plants. Many say to change half the water, but 25-33% should be fine.

An accumulation of waste in dirty water can lead to a build-up of ammonia, nitrites, and nitrates, which are all poisonous to fish. You can buy cheap test strips that tell you when these levels are getting high and when the water needs changing to ensure you keep goldfish healthy.

Finally, be sure to keep an eye on the temperature of the water, as it’s always best to keep your tank or fish bowl at a consistent temperature. By following these simple tips, you can help to ensure that your goldfish have access to high-quality water at all times.

Best Aquarium Filters for Goldfish

So, we’ve established that getting an aquarium filter for your pet goldfish is a good idea to maintain water quality.

However, which type of filter should you get? Thankfully you have plenty of options available for a good filtration system so let’s take a closer look.


A sponge filter is an excellent option for goldfish tanks for several reasons. First, sponge filters provide biological filtration with beneficial bacteria, which helps to keep the water clean and healthy. Second, sponge filters effectively remove suspended debris from the water column.

This can help to improve water clarity and reduce the risk of disease. Finally, sponge filters are relatively easy to maintain and can be used in fresh and saltwater aquariums.

For all these reasons, sponge filters are an excellent choice for goldfish tanks.

Hang On

When it comes to filtration, hang-on filters are an excellent option for goldfish tanks. Hang-on filters attach to the back of the tank or goldfish bowl and hang over the edge, making them easy to install and maintain. Also, hang-on filters come in various sizes and styles to suit any goldfish tank.

One of the most significant advantages of hang-on filters is that they provide excellent filtration without disrupting the flow of water in the tank. This is important for goldfish, as they are susceptible to changes in water flow.

Hang-on filters also offer a high degree of customization so that you can tailor the filtration to your goldfish’s specific needs.


A canister filter is an excellent option for goldfish because it provides superior filtration and circulation while taking up less space than other filters. Your local fish store will most likely stock them.

Canister filters are designed to be hidden away so they don’t take up valuable real estate in your tank. They also offer a higher flow rate (amount of water cycled) than other types of filters, which is important for goldfish because they are such messy eaters.

Goldfish produce a lot of waste, and a canister filter will help to keep the water clean and clear. In addition, canister filters tend to be very quiet, which is an important consideration if you want to create a peaceful environment for your goldfish.


Final Thoughts

As anyone who has ever kept a goldfish knows, they are fairly low-maintenance pet fish. They don’t need much attention and can go for long periods without being fed. However, one area where they do require some attention is their water filtration.

While goldfish can withstand lower levels of water quality than other fish, they still need a filter to remove debris and toxins from their environment. A filter also helps to create a more stable water temperature, which is essential for goldfish health.

Goldfish are more likely to succumb to disease and stress without a filter. As a result, it is crucial to ensure that your goldfish have access to a high-quality filtration system. Just because they can survive for a while without a filter, it doesn’t mean it’s the right thing to do.

Kelly Stanley