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How often should you clean a fish tank?

Fish tank with aquatic plants on black background

To keep your fish happy, it’s important to clean your tank often. Nobody likes to live in a dirty home, and that includes pets. However, for a fish to live in a dirty tank can be life-threatening. Keeping a balance of beneficial bacteria, nitrates, and oxygen in your tank is crucial to the health of your fish. Consequently, no one fish tank will require the same amount of care and cleaning. There are several factors that will affect just how often you should be cleaning your fish tank. Keep reading to find out how often you should be cleaning your fish tank, and how to keep your fish at their happiest and healthiest. 

Why you need to clean your fish tank 

It’s hard to feel great in a dirty space. Just picture how you feel when you’re in a dirty home. It’s difficult to relax and get comfortable, and you can’t help but feel dirty yourself. Now imagine that you had to breathe in and be completely immersed in all of that dirt and waste. Well, that is exactly how your fish live. Our fish live in and breathe in all of their own waste, discarded food, and algae. This is of course inevitable unless you miraculously learn how to potty train your fish, but the amount of waste present in their tank can be controlled and maintained to keep your fish at their healthiest. An imbalance in bacteria, nitrates, and algae can threaten the lives of your fish, as well as make your tank appear dirty and smell foul. Just like you need to pick up after your dog and keep your home tidy, the same needs to be done for your fish.  To keep your fish healthy, it’s important to clean your fish tank often, but not too often. So how often is too often

Tropical fish tank filled with aquatic plants and orange fish

How often you should clean your fish tank

Fish tank maintenance can be complicated, and even involves a bit of math. Ultimately, the frequency at which you need to clean your fish tank will depend on a number of factors; the number of fish in your tank, the size of your tank, the production of nitrates by your fish, and your method of cleaning. There is no one answer unfortunately to how often you should clean your tank, but every tank is unique and requires special care instructions to keep it at its best. 

In order to determine when it is time to clean your fish tank, you need to first test the nitrates in the water. The nitrates in the water are produced by your fish’s waste. If the nitrates are too low or high it can negatively affect your fish’s health. The number of algae in the water can also affect oxygen levels in the water. In order to control the nitrates, you will need to change the water to get the water back to a healthy nitrate level, without changing so much water that the change can shock the health of your fish

Most people want to do a cleaning task as infrequently as possible, and luckily there is no exact schedule for tank cleaning. This time period depends on your filtration system, type of fish, size of the tank, and nitrate level. Depending on these factors you can clean your tank anywhere from twice a week to once a month[1]. Cleaning your fish tank once a week is a good rule of thumb to follow, as it is not so frequent that it will cause stress to your fish, but not so infrequent that your quality of water will degrade. Always follow the advice of your aquatic veterinarian when determining your needed frequency of cleaning.

How do you clean a fish tank?

Changing the water:

Changing the water in the tank is an important part of cleaning, as it controls the PH level of the water. Fish waste releases ammonia as it decays, which then turns into nitrates “as bacteria break it down which creates a pH imbalance”[1]. If your fish thrive off of bacteria and nitrates, it’s best to replace the water in smaller percentages. That is why it’s so important to use a nitrate testing kit. Depending on your type of fish you will want to keep the nitrate level at a certain percentage. If the nitrate level is too high, replace more water, if the nitrate level is too low, replace less water, or wait longer in between replacing the water. Changing your water can be done anywhere between twice a week, to once a month depending on the nitrate level, and filtration system. 

Gravel cleaning:

The gravel at the bottom of your tank can trap fish waste and discarded fish food. This waste can grow bacteria and throw off the equilibrium of your tank, even if it looks clean. You should use an aquatic vacuum to clean the gravel in your tank at least once a month[1].

SLSON Aquarium Algae Scraper Double Sided Sponge Brush Cleaner Long Handle Fish Tank Scrubber for Glass Aquariums and Home Kitchen,15.4 inches

Removing algae:

Once a month when you vacuum your aquarium gravel you should take this time to also scrape any excess algae on the walls of your tank. You can use a sponge scraper to do this. Algae in a tank are generally beneficial, as algae produce oxygen in the daylight. However, “too many algae can actually cause problems for fish by raising the pH too high, starving the tank of oxygen at night, blocking filters, and trapping fish”[2]. Keep the balance of algae by scraping any excess on the sides of your tank once a month.

What you need to clean a fish tank

Nitrate testing kit:

A nitrate testing kit will allow you to test the nitrate levels in your fish tank. These test strips will allow you to determine how much water you will need to change on your next tank cleaning to keep the nitrate levels at a good level for the health of your fish. 

6 in 1 Aquarium Test Strips,100 Strips Fish Tank Test Kit for Testing PH Nitrite Nitrate Chlorine General & Carbonate Hardness, Accurate Saltwater and Freshwater Aquarium Water Testing

Algae sponge scraper:

An algae sponge scraper is used to remove excess algae from the sides of your tank. If there is a build-up of too many algae in your tank it can actually begin to trap the oxygen that your fish need. A sponge scraper will clean the sides of your tank making it look cleaner, and benefit the health of your fish. 

Lystaii 3pcs Aquarium Algae Scraper, Double Sided Sponge Scrubber Tank Brush Cleaner Long Handle Marine Fish and Reef Aquarium for Home Glass Aquariums

Aquatic vacuum:

An aquatic vacuum is crucial for cleaning your aquatic gravel. It vacuums up fish waste, discarded food, and excess algae. With an aquatic vacuum, you can easily clean your gravel without having to empty your tank and clean the gravel by hand. 

Hand cleaning fish tank with aquatic vacuum

Clean tank, happy fish

While there isn’t a particular schedule you must follow when it comes to cleaning your fish tank, a good rule of thumb is to clean your tank about once a week. That way your fish feel as good as your tank looks, but you don’t have to set out a huge chunk of time to get the job done. The longer you wait between cleanings could mean the task will be more difficult to complete. 

Fish are in a unique position in that they have to not only live in their mess, they indirectly eat it, and breathe it in as well. An imbalance in bacteria in your fish tank can make it look dirty and dingy, and affect the health of your fish. Maintaining an equilibrium of bacteria, nitrates, oxygen and algae is so important in your fish tank. To keep your fish happy, healthy, and your tank looking your best, aim to clean your tank once a week. Always refer to the advice of your aquatic veterinarian when deciding your cleaning frequency and cleaning method. Your fish will look and feel better in a sparkling clean home! 


Article Sources:

  1. Animal City Inc. “How Often Should You Clean Your Fish Tank
  2. Swell UK. “How t0 get rid of algae in a fish tank naturally