How do You Clean Goldfish Tank Water?

This post contains affiliate links.

Keeping goldfish as pets comes with chores. One of them is keeping your tank clean and making sure the water levels are right for your goldfish. And now you might be wondering how to properly clean your aquarium. In the following, we explain exactly how and how often to clean your tank to make sure that your fish are safe, healthy, and happy.

As a whole, goldfish tank water can be cleaned through regular water changes of around 50%. The gravel can be cleaned in the tank, while the filters and decoration can be taken out and cleaned with old aquarium water. Freshwater has to be treated before it is poured into the aquarium.

How do You Keep Goldfish Water Clean?

The aquarium is the goldfish’s home and it is also an ecosystem that has to be kept nice and clean to make sure, your goldfish get the healthy and good life they deserve. 

Cleaning is the most obvious component when it comes to keeping the water clean. But the right tank equipment, the water quality, and some fish species that help you to keep the algae growth under control are also useful factors when it comes to clean water in the tank.

Regular Water Changes

The most important part to keep your water clean, are regular water changes. These are essential because goldfish produce a lot of organic waste and can easily poison themselves.

Preparations for a Water Change

Before you start with the water change, you will have to prepare a few things.

  • Buckets of water
    • Temporary goldfish home: You need a container as a temporary home for your fish during the water change. This is not obligatory but recommended, as goldfish tend to be stressed quickly. You can use the water from the aquarium for this temporary home or clean water that has been pre-treated to eliminate chlorine, chloramine, and any heavy metals or chemicals.
    • A bucket of water to clean filters if necessary. Never clean filters under running tab water.
    • One empty bucket for the old aquarium water.
  • Water
    • Aged water: You can prepare a tank full of tap water 3 days before you are planning to do the water change. The water will lose the chlorine and chloramine to the air, but you should still do a test of the water parameters before you use it. Some fish-owner use aged water and add some treatment to make sure, all chemicals are gone.
    • If you want to use tap water directly, you have to remove the fish from the aquarium. You can use a hose that goes directly from the water tap into the aquarium. 
  • Water changer hose / Aquarium vacuum: This comes in handy to get the water out of the tank. Secure some kind of lid, such as a net or cloth on the opening of the hose with rubber to prevent goldfish from getting hurt or sucked in.

Now that you have prepared all the equipment, it’s time to check the water parameters. These are the parameters you are always aiming for:

  • Ammonia: As close to zero as possible, between 0-0.25 ppm is tolerable.
  • Nitrite: As close to zero as possible. Under 10 ppm is tolerable.
  • Nitrate: Below 40 ppm is ok.
  • pH: This shows how acidic or alkaline the water is. 7.0 is neutral. A good level for a goldfish aquarium is between 7.4 and 7.9.

Depending on the water level you can decide if you want to do a 40% water change or more. 

The last thing before you start cleaning is to unplug everything to avoid any potential accidents.

How to do the Water Change in the Aquarium

Make sure that all electric devices are turned off and plugged out. 

Remove your goldfish from the aquarium

Before you start cleaning, you might want to take the goldfish out of the aquarium to reduce any potential stress.

Use the container that you prepared with the water from the aquarium or with fresh but pre-treated water and gently catch the fish with some kind of container to avoid any injuries. Place it in the temporary tank.

Clean the Glass

Use your mag float to clean the glass, or if the algae do not come off, use a razor blade or a plastic blade if you own an acrylic tank. Otherwise, you might scratch the acrylic glass.

It is ok to leave some algae on the glass. Those are good to maintain healthy water levels for your fish.

Water Change

If you use aged and/or pre-treated water, place it close to your tank.

Also put a big, empty bucket close to the tank for the “old” water. 

You will need an automatic or manual aquarium vacuum or any kind of water hose to drain the water out of the tank. 

Make sure, that the bucket for the old water is safe and cannot be spilled. If you have a dog or cat, make sure, that they don’t knock over the bucket.

Drain 40-60% of the tank water in the bucket. Maybe you want to empty the bucket a few times if the bucket gets too heavy to carry. The amount of water change depends on how dirty the water was and how good or bad the water levels were.

Draining the water can take some time. Be patient, it will lead to a happy and healthy goldfish.

Clean the Gravel

Go through the gravel with a gravel cleaner, the end of the aquarium vacuum, or simply use your hands to mix up the gravel and thereby clean it from any waste or leftover food. Do not remove the gravel from the tank and never wash it in tap water. The gravel is home to many beneficial bacteria that help you to regulate the nitrogen cycle, breaking the poisonous ammonia down and making it less harmful for your goldfish. 

If might see the gravel swim into the aquarium vacuum but the weight will prevent it from being removed through the hose.

Clean the Filters

Be careful with the filters. They are home to many beneficial bacteria, that regulate the nitrogen cycle. They can also be quite messy, and you might want to put on some rubber gloves.

Clean the filters in the prepared bucket of “old” aquarium water. Never clean them in untreated tap water. Otherwise, you will get rid of the beneficial bacteria and would have to cycle the tank again. 

If you want to be safe, clean gravel and filters separately on different days to make sure, there’s always enough beneficial bacteria in the tank.

Clean Decoration

Clean the decoration just like the filters in aquarium water. Never use untreated tap water. You don’t have to clean plants or real rocks.

Refilling the Water

Now that everything is clean, it’s time to refill the tank. 

Use the aged water if you have some prepared. If not, you can pour tap water into the empty bucket. Try to use lukewarm water, which is close to the temperature of the water that was in the tank before. 

Before you pour the water into the tank, you will have to treat it with some de-chlorinator, which will help you to get rid of chlorine, chloramine, or any heavy metals in the water. Read the instructions of your treatment and make sure to follow them. 

Never use tap water directly in the aquarium. This can kill all beneficial bacteria and can burn the goldfish’s gills and skin. It can even lead to the death of the goldfish. Always treat the water before pouring it into your tank.

After treating the water, let it sit for several minutes. Once it had enough time to do its work, you can add it to your tank. 

Don’t rush it to prevent any mess. Take your time in filling the tank gradually.

Make sure all levels are safe for your fish before you place him back in the tank. Check the temperature (between 66 and 74°), pH, ammonia, nitrite, and nitrate levels. 

Put all your decorations and plants back in the tank.

Turn on your tank equipment

After everything is done, it’s time to turn your tank equipment back on. Let the filter and air pump run for several minutes to bring the oxygen level back to where it used to be before you let the goldfish back in the water.

Put your goldfish back in the tank

Now you can put your goldfish back in the tank. Offer your pet a little treat and make sure that he or she is relaxed and happy.

Tank Equipment

Good tank equipment is very helpful to keep your water clean. If your tank is properly equipped, you will have to do fewer water changes (but still at least once a week!) and the tank will not appear cloudy or dirty.

A good filter system will help you to maintain the correct water levels for your goldfish. Since goldfish produce more waste and need more oxygen than other fish species, you should choose a filter system for a tank about 3-10 times the size of what you own. This seems like a lot but is necessary to keep your goldfish healthy. You can also have several filters if you don’t want one powerful filter. 

You can also acquire an air bubbler in addition to one filter to make sure that you always have enough oxygen in the water and that the water is always moving to distribute the oxygen properly. 

Another decorative piece of equipment you can get are plants.

They keep the water levels at a good level. Goldfish like to nibble on the plants and will dig them out if you try to fix them in the gravel, but most plants will survive. Since plants keep the nitrate levels low, they are a great acquisition.

Water Quality

Clear and clean water are not necessarily the same. Water quality is essential for your goldfish’s health. Even though tab water or bottled water may appear clear, they are not clean for your goldfish.

To make sure, that the water levels are always safe for your fish, you should do regular tests with test kits.

In a properly cycled tank, the ammonia and nitrite levels should be as close to zero as possible, nitrates should be below 40ppm and there should always be enough oxygen in the tank.

An aquarium, that appears cloudy or with extreme algae growth is not perfect and should be checked and cleaned. 

Best Fish that Keeps Your Water Clean

If you decide to introduce some other fish to your goldfish tank, you might want to go for fish species that keep your tank and water clean.

You need coldwater fish, that can thrive in the same water conditions as your goldfish needs. The fish should not be too small, or your goldfish might be tempted to eat your new fish as a snack. The fish should also not be aggressive or too energetic, because your goldfish can easily get stressed. 

These fish, snails, and shrimp can be a good company for your goldfish and clean your water and tank:

  • Gold ring hillstream loach:

This loach likes fast-flowing waters that are rich in oxygen, just like the goldfish does. It is also happy at a similar temperature as the goldfish. They love to eat all the algae in the tank.

  • Rubber Lip Pleco / Bulldog Plec

The rubber lip pleco also referred to as Bulldog Plec, is a freshwater fish. They like to eat the algae in the tank and also veggies or algae-based food. Only the algae in the tank might not do it, but they will keep the aquarium clean for you.

  • Peppered Cory

The peppered cory is a pretty, small, and peaceful fish that does not eat algae but will eat all uneaten food from the ground. This will lead to a sparkling clean floor. They are schooling fish, therefore a minimum of 5 fish are necessary to make them feel safe.

  • Ramshorn snail

The ramshorn snail can multiply very quickly and the breeding can get out of control. But they do love algae and if you have a way to control them, they are a great way to get your tank algae-free.

  • Nerite snail

Nerite snails also love algae and also multiply quickly, but not as rapidly as the ramshorn snail.

  • Amano shrimp

These tiny see-through shrimps are often hidden in plants and eat algae and leftover food all day long. Since they are tiny, goldfish might be tempted to eat them.

Common pleco: Watch out, the Common pleco is often sold as the perfect solution to clean a tank. But these plecos can grow up to 24 inches and have a lifespan of 10-15 years.

When you buy them in a pet store, they look cute and tiny, but after a few years, they are huge and will be laying on the ground, producing waste and poop. Often people try to get rid of them and they end up as rescues. 

How Often Should Goldfish Water be Changed?

The frequency of the water change depends on several factors. 

Make regular tests of the water parameters to check if cleaning and water changes are necessary.

The smaller the tank, the more frequent you will have to clean it. The more fish you own, the more waste will be produced, and the more often you will have to do water changes.

As a rule of thumb, you can clean your tank at least once a week with a minimum of 50% water change.

In many tanks, a more regular water change of 50-90% every 3-5 days is necessary. But it always depends on the water levels and how dirty the tank and water are.

Where do I Put my Fish When Cleaning the Tank?

You can pour some water from the tank into a separate bucket and put your fish in that bucket. You can catch them with a small container to prevent any injuries and stress.

If you only to 30-40% water changes, you could even leave the fish in the tank. But that depends on how easily stressed your pets are.

If you want to reduce stress and are unsure how tolerant the fish is, better put it in a temporary tank.

Can I Use Tap Water for Goldfish?

Tap water without any treatment is not safe to use for your aquarium. The chlorine, chloramine, and heavy metals can kill a goldfish and destroy all the beneficial bacteria that grow in the tank. 

You can only use tap water, once it was treated with dechlorinator. 

You can find more about water for goldfish here:

Leave a Comment