Cleaning a fish tank is an important part of keeping a healthy fish tank. However, knowing what you should do (what you shouldn't do) and how to clean the aquarium isn't easy to do. In fact, if you ask questions at the pet store or the fish store you may even get some terrible advice, conflicting advice, and some ideas that will make it worse. The good news is that you don't really have to spend a lot of time cleaning the fish tank and you can do a good job. It is lots easier than many people believe.  

Aquarium with Guppies

Why Do Aquarium Water Changes?

The simple answer is, “Would you want to swim in your waste and never get the water changes?” However, it is a little more complicated than that and that idea might have you changing the water more than once a day. The process is known as the nitrogen cycle. It all begins with fish waste, left over food, and or decaying plant matter. Each of these things adds ammonia to the water which is poisonous to the fish and other creatures in the tank. However, as your fish tank ages it will grow bacteria that will consume the ammonia and turn it into nitrites. The nitrites are still dangerous to the fish and creatures, but another type of bacteria will grow in order to consume the nitrites. They will in turn release nitrates. Nitrates aren't as dangerous for your fish which allows them to swim in it a lot longer than they can the ammonia or nitrites. However, aquarium water changes are the primary way to get rid of nitrates in your fish tank. They are important for keeping your fish tank clean and your fish healthy.  

How Do You Do Aquarium Water Changes

Many people think of the aquarium water changes as a huge project, even for a little fish tank. The good news is that it isn't that difficult.

Remove the Water – The first step you should do is remove water. How you will do this will depend on the size of your fish tank, how many fish tanks you have, and how much money you want to spend on the job. Your options include:

  • A Cup or Bowl – If your job is small or if you don't have a lot of money to spend on getting equipment then you can get a cup or a bowl and remove the water.
  • An Aquarium Water Changer/Siphon – You can get an aquarium water changer or siphon. With a small variety you can siphon the water into a bucket or trash can. Larger varieties hook on to the sink using the sink water to start the siphon.
  • An Aquarium Vacuum – While most of the aquarium water changers and siphons are capable of vacuuming the substrate, you may want to get a small hand-held vacuum. This makes it possible for you to use it for water changes in small aquariums where larger water changers or siphons wouldn't work. You can also use it for vacuuming if you choose to do this.

Add Fresh Water – Once the water has been remove you need to fill the tank back up. You need to make sure that it is chlorine free by using water that has sat out with a large open surface for 24 hours or by adding a water treatment to the water before you add the water to the tank. If you are adding untreated water to the tank and treating it there you must make sure that you use the whole tank is treated. To add the water you can use one of these methods:

  • A Cup or Bowl – You can use a cup, bowl, bucket, and even a clean trash can is one way you can add water to the fish tank.
  • Aquarium Water Changer/Siphon – If you buy a long (more expensive) water changer that hooks up to the sink then you will be able to reverse the flow and have the sink fill the aquarium for you. Just make sure you pay attention to it so you don't flood the area around the aquarium.

As long as your tank is healthy then you should only do a water change once a week and you should only need to remove 25% of the water. However, if there are any problems than you can do a larger water change (as long as you have hardy fish) and you can do them more often. There are also ways to reduce the amount of water changes. If you are interested in this you can check out the article Reducing the Aquarium Water Changes And Still Have a Clean Fish Tank.  

An Aquarium Siphon
Credit: Amazon

Cleaning a Fish Tank

There are a few other things that you may want to do when cleaning a fish tank. However, because you won't really be cleaning the tank and you want to make sure that you don't clean off all the bacteria that consumes the ammonia and nitrites.  

  • Cleaning the Substrate – You don't have to clean the gravel, sand, or other substrate. However, over time it may look like it is getting dirty. Two ways to clean the substrate include mixing up the bottom to have the “gunk” float around and then siphon or scoop the water out of the tank during your normal aquarium water changes. The second option is to use a gravel vacuum. You can buy a water changer or siphon with a vacuum that can be used to suck the stuff out of the gravel while doing your normal water changes. In either case it is best if you only do this sort of cleaning once a month so as not to disrupt your biological filter (all those good bacterium).
  • Cleaning the Glass – The fish never care if you have dirty glass in your aquarium. However, it can make it hard to enjoy your tank. You should clean the glass on a different day then you do your water change so you keep as much of your bacteria as possible. It's also a good idea to do two glass walls in one day and wait a bit before doing the others or only keep the front really clean. This isn't a must do so you can do it when you feel you really want to or you must do it. 


Filter Care

No matter what type of filter you choose to have you want to make sure that you are keeping it clean. It is important to avoid rinsing your biological filter media on the same day that you do a water change. If using activated charcoal then you should follow your filter's instructions to keep your filter doing it's job.  

What You Shouldn't Do When Cleaning a Fish Tank

When I bought my first aquarium in college I did some of the things that I have heard others do that you definitely shouldn't do. However, for the health and wellness of your fish you should never do these things even if someone says you should.

  • You should never remove your fish when cleaning the fish tank. This is the biggest thing that I did that a lot of others do. I scooped up all of my fish, drained all the water, vacuumed the gravel while it was draining, scrubbed the walls and decorations clean, and even cleaned the filter in one giant sweep. I put everyone back and was pleased with my beautiful fish tank. However, this kills all of the helpful bacteria (leaving your fish swimming in their own waste) and can cause a lot of stress and even death to your fish.
  • Never put cleaning chemicals into the fish tank to clean it. You shouldn't use ammonia, bleach, or other chemicals on the inside of the fish tank or on any decorations or substrate that go into the fish tank. This also includes using dish soap on any of these surfaces. You should also be careful spraying chemicals on any of the outside surfaces as well including glass cleaner which often has ammonia in it. Instead, spray the cleaner onto a rag and use that on the glass.
  • Never do all of your cleaning at one time. I have seen sites and people who look like they should know what they are talking about tell you to do all of the cleaning at one time. Some say this is “deep cleaning”. Some recommend doing it less often then regular cleaning. However, no matter what authority they may have, the science behind it is very faulty because it kills too many of the healthy bacteria your tank needs.  
Baby Crayfish in Aquarium

I learned the hard way and after years of fish keeping, tons of research, and a bit of trial and error I can tell you that cleaning the fish tank and doing regular water changes doesn't have to be a big chore. In fact, it's bad if it is a big chore because it means that you are doing too much! It only takes a bit of work and you can have the tank you deserve.