How to Clean a Goldfish Tank [5 easy steps to keep your Goldfish healthy]
Goldfish aquariums are wonderful ecosystems that thrive with safe, clean water. If you’re wondering how to clean your Goldfish tank, then this article is the right one for you!
Cleaning a Goldfish tank means taking care of your water by removing waste from it and excess food. Keeping your tank and decor clear of algae as well as maintaining your equipment like filters and tubing is critical. With regular water changes, quick weekly cleans, and occasional deep cleanings you will keep a happy healthy Goldfish!

Keep reading to learn everything you need to know about keeping your Goldfish tank clean and healthy!
What Makes Goldfish Unique?
Goldfish, also known as Carassius auratus, is a popular type of ornamental fish. These omnivorous fish can live up to ten years in aquariums or more than 30 years in ponds.

There are over 300 types of Goldfish with distinct colors, fins, eyes, and body shapes. The most common types of Goldfish are common, comet, and fantail Goldfish.
Rare Goldfish Types
More Rare breeds include nankins, panda moors, and meteor Goldfish.
Selecting the right type of Goldfish comes down to what size tank you have, your level of experience, and how much you want to invest.
It’s usually best to start with the easier common breeds and work your way toward fish that require more time and expertise.
Can Goldfish Learn Tricks?
Contrary to what you hear, these fish don’t have a five-second memory.
They’re quite good at remembering events for several months, and they can learn simple tricks like swimming through hoops or obstacle courses.
Why Do You Need to Change GoldFish Tank Water?
Our primary concern for cleaning a fish tank is removing waste. Dirty water comes from fish waste, fish scales, decaying plant matter, dead fish, overcrowding, and extra food.

Each of these fouls the water over time. The decaying matter is especially problematic as it increases ammonia and nitrite levels which can harm your fish.
Is Dirty Water Unhealthy For Your Goldfish?
Other water issues include algae outbreaks and inadequate filtration. Goldfish in dirty water are more susceptible to illness and diseases, parasites, and dropsy.
At its worst, water can become unlivable as elements like ammonia and nitrite physically injure your fish.
Dirty tank water also holds less oxygen, which makes it more difficult for your Goldfish to breathe.
Why Does My Fish Try to Jump Out of the Water?

If your fish tries to jump out of its water, this could mean that there is something very wrong with your water.
The usual culprits are high ammonia or pH levels as these deplete oxygen levels and slowly suffocate your fish.
Chemicals like ammonia can also hurt your fish by burning their gills, causing pain, and making it hard for them to breathe.
Regular water changes and cleanings will help keep your water clear, fresh, and free from these harmful elements.
Required Goldfish Fish Tank Water Quality
No one wants to drink a glass of water filled with algae or biological waste. Just as we prefer to drink clean, safe water to drink, so too do fish prefer clean water to live in.
How to Test Your Goldfish’s Tank Water

It’s important to test your water parameters for a range of variables, and these can include:
- Alkalinity
- Ammonia (NH3) and ammonium (NH4)
- Carbonate hardness (KH)
- Chlorine and chloramines
- General hardness (GH)
- Nitrite (NO2) and nitrate levels (NO3)
- pH
For simple testing, you can test the basics:
- Chlorine and chloramines
- Ammonia (NH3) and ammonium (NH4)
- General hardness (GH)
- Nitrite and nitrate levels
- pH
Always keep a water test kit or test strips on hand. These will help you check within minutes to see if you have a water problem and what that problem might be.
Timing Is Everything With Goldfish
Timeliness is vital when taking care of your Goldfish. When in doubt new water is always the best option!
If you don’t have access to a test kit or strips, you can usually take a water sample to a local pet store, and they’ll test the water for you.
Make sure you transport the water in a clean, chemical-free container.
How To Treat Goldfish Tank Water
Tap water and bottled water are treated to remove bacteria, viruses, and microorganisms from drinking water. But what makes water safe for us makes it harmful to Goldfish.
A good water conditioner is vital for removing deadly metals and chemicals from new tank water.

Water conditioners break these elements down into harmless chemicals, making your water safe for your Goldfish.
There are a variety of water conditions available online or at your local pet store. Follow the instructions on the label for the best results.
How to Change Your Goldfish’s Aquarium Water
First, you’ll need a few tools:
- Gravel siphon or aquarium vacuum
- Algae scraper
- Bucket
- Paper towels
Next, you’ll need to have prepared enough fresh water ahead of time so that you can replace the water after you’ve removed some of it.
Safety First When Changing Fish Tank Water!
Be sure to unplug equipment like your filter or air pump, light, and heater because electricity and water are not a good combination.
Turning the heater off is especially important, as it can crack or cause damage if left on when it’s not fully submerged.
What Do I Do With My Goldfish When Changing Tank Water?
Most fish will stay out of your way as you clean the tank. If you work slowly and gently, they’ll be fine to hang around.
If you’d rather not do this, you can gently catch and place them in a breeder box inside your tank, or you can move them to a temporary container, holding tank, or bucket if you have one.
Never put Goldfish in a container that has been cleaned with chemicals like dish soap. These chemicals stay in the container and will leach into the water and make your fish sick.
What Items to Clean in a Goldfish Tank
At a minimum, you’ll likely have most of the following in your tank:
- Filter
- Heater
- Thermometer
- Substrate
- Plants and decor
- Lighting
- Air stone or bubbler
You’ll need to clean all these items when deep cleaning your tank, but it’s unnecessary when doing quick weekly maintenance cleanings.
Five Easy Steps to Cleaning Your Goldfish Tank
Follow these five simple steps to give your Goldfish aquarium a thorough cleaning.
1) Clean the Glass
Cleaning the inside of your tank glass helps remove algae growth to prevent new or worsening algae issues or even an algae bloom.
Use a magnetic or handheld algae scraper to gently lift algae growth off the glass.
You might need to adjust the light and your viewing angle to see some growth, and a flashlight or table lamp will help you.
It’s easier and safer to move your body around the tank than it is to move the tank around.
You can clean the outside of your glass with a fish-safe, chemical-free cleaner. Spray a small amount on a paper towel and gently wipe in a circular motion.
2) Clean the Substrate
Substrate, the material you add to the bottom of the tank, like gravel or sand, collects waste and other debris.
Use your gravel siphon or aquarium vacuum to remove waste and debris from the bottom of the tank.
Have your bucket handy to catch the excess water and use your paper towels to wipe up any drops on or around your aquarium. It’s at this stage that you’ll remove most of your water.
Never change more than 50% of an aquarium’s water at one time, as this will damage the beneficial bacteria population and the nitrogen cycle.
Instead, aim to remove about 10-20% with a weekly change and up to 40% with a deep cleaning.
3) Clean the Plants, Decor, and Equipment
Never rinse your live plants or artificial plants, decor, or equipment in untreated tap water as the chlorine and chloramines can transfer into your tank.
It will also kill your good bacteria, and, with the large water change, this will negatively impact the ecosystem in your tank.
Use the bucket or container that you drained tank water into as a place to rinse your plants, decor, and equipment.
4) Clean the Filter Media
You should also use the water drained from your tank to rinse your aquarium filter. Submerge the filter media and gently move back and forth or squeeze.
You’ll likely see your filter release some waste, but it’s okay if your filter still looks “dirty” as that’s the beneficial bacteria!
There’s no need to keep replacing your fish tank filter, as your pet store or product description might recommend.
That’s because your beneficial bacteria colony lives in your filter and replacing the filter media can damage or crash your nitrogen cycle.
5) Add Fresh Water
Ideally, you would have added your tap water to a container at least 24 hours in advance to let the water temperature acclimate to room temperature.
You also would have treated it with a water conditioner and given it time to settle.
When adding your new tank water, do so slowly and gently. It helps to pour it against the inside of the glass or on some decor to break up the flow.
This will help stop your fish from swirling around with the sudden flow of water.
Be mindful of the temperature change happening in your tank, even if your water is at room temperature.
Extreme temperature changes are like sitting in a hot bath while someone throws a glass of icy water at you. It really shocks your system.
How Often Do I Need to Clean My Goldfish Tank?
A complete, deep tank cleaning doesn’t need to happen very often, only about once every few months. Light cleanings and a partial water change of about 10-25% should occur weekly.
The frequency of cleaning your tank will vary based on the size of your tank, how many Goldfish you have, and how many other animals you have in the tank.
From tiny snails to large fish, the more life you have in your tank, the more waste they’ll produce.
Smaller tanks are more sensitive to changes, so deep cleaning should happen once a month to avoid issues like harmful bacteria growth or ammonia spikes.
Related Goldfish Questions
How do I clean a Goldfish tank without a filter?
If your tank doesn’t have a filter, you can use your hands to stir the gravel, then use your gravel siphon or aquarium vacuum to remove the waste in the water.
How do I clean a Goldfish tank without a vacuum?
If you don’t have a gravel siphon or aquarium vacuum, you stir the gravel with your hands to release the waste, then scoop out a third of the water with a bowl. You’ll need to do this at least weekly.
Do Goldfish need light at night?
No. Because Goldfish don’t have eyelids, they cannot close their eyes, so they need about eight hours of darkness at night to rest their eyes.
Should I put my Goldfish tank in direct sunlight?
No, you should not locate your Goldfish tank in direct sunlight. Your tank should be in an area where it gets some indirect sunlight.
A small amount of direct sunlight probably won’t hurt but you have to make sure it does not warm the tank water too much!
Too warm of water can cause a multitude of problems which include algae growth and possible harm to your Goldfish.
How big will my Goldfish grow?
A Goldfish will grow as big as its tank. If you have a small tank, your Goldfish will stay more but will not be healthy. If you have a large tank, your Goldfish will grow bigger.
How old is my Goldfish?
Every year that a Goldfish lives, it develops a ring on each scale. If you count the rings on one scale, you can tell how many years it has lived.
How to tell if my Goldfish is happy?
It’s hard to tell if a fish is happy, but if you provide everything they need, like tank maintenance and food, then it’ll likely be a very happy fish.
Pros and Cons of Goldfish as Pets
Goldfish are a striking addition to any fish tank. Because of their long history of breeding, common Goldfish are a little hardier than rare types that will need extra care.
Regardless of their breed, all Goldfish need clean and safe water to thrive. Without this, they’re at a much higher risk of diseases, parasites, and death.
If you don’t have the time for this requirement a Goldfish may not be a good choice for you.
Simple weekly water changes and cleanings will keep the ecosystem in your tank thriving. Deep cleanings will ensure that your tank stays safe and stable for your Goldfish.
Goldfish can be great pets and a fun addition to your family for the right person.
