How To Clean A Tropical Fish Tank (and Other Aquarium Maintenance Questions)

Tank maintenance is one of those less than glamorous things nobody really talks about when discussing aquariums. However, in order to keep your fish happy and healthy, a regular maintenance routine is indispensable. Maintenance on freshwater and saltwater aquariums are different, so this article will focus on freshwater and tropical tanks, and you can check this other article for information on marine aquariums maintenance.

Freshwater Aquarium Maintenance Supplies

Some aquarium gravel syphons can be attached to the tap. A must have for large aquariums
Some aquarium gravel syphons can be attached to the tap. A must have for large aquariums

Doing a water change and cleaning the aquarium can be a bit of a messy job, particularly if you have a large aquarium. Wear clothes you don’t mind getting wet, and if your floor is very delicate put towels around the place and be extra careful.

Other things you may need are:

  • Water and water conditioner, such as seachem’s Prime
  • An aquarium algae scrapper or a dedicated sponge
  • A big bucket. If somebody is helping you, two buckets make moving water more effective
  • A syphon gravel vacuum
  • Filter media (remember not all your filter media needs to be changed at the same time)

If you want to use rubber gloves, make sure they are aquarium safe and haven’t been treated with chemicals

10 Steps Aquarium Maintenance Routine

African cichlid aquarium
African cichlid aquarium (Photo credit: Wikipedia)

Most people do some form of maintenance at least once a week, but the perfect schedule will depend on the requirements of your fish. Generally speaking, small water changes performed often are better than very large but infrequent water changes. However, it will all depend on your fish and your aquarium setup.

  1. Turn off the aquariums lights and filter. You don’t want your filter running when you start removing water from the aquarium. Remove the aquarium top and put it somewhere safe and out of the way.
  2. If you can, turn off any electrical switch near the aquarium. Water and electricity are a very bad combination.
  3. Using an algae scrubber or a sponge wash our the inside walls of the aquarium and remove algae.
  4. Usually you need to change between 10 to 20% of the water every week. However, if your fish are sick or you are cycling the tank you should perform more frequent and regular water changes.
  5. Use the syphon to syphon the required amount of water from the aquarium. Syphon waste from the ground of the tank, pushing the vacuum into the gravel. HOWEVER, only do this in half the tank at a time. This way you won’t be syphoning out all of the bacteria that perform the nitrogen cycle.
  6. Clean the decorations with the algae sponge or an unused toothbrush. If your decorations are covered in algae you can take them out and put them on a 10% bleach solution for 15 minutes, then wash the bleach off with boiling water and let them air dry. Consider adjusting your feeding and maintenance routine if algae are a problem.
  7. Prepare replacement water, treating it with a water conditioner and bringing it up to aquarium temperature before you pour it into the tank. If it feels hot to the touch, is probably much too hot for your fish.
  8. If you use freshwater salt, add it to your replacement water now.
  9. Open the filter and replace the filter media as required.
    1. If your aquarium is brand new and you are doing fishless cycling it’s better not to disturb the filter media as bacterias will be colonising it, but you can rinse it in the old aquarium water to remove the bigger particles.
    2. If your aquarium is under 3 months, and to avoid new tank syndrome, replace only half of the filters and leave the other half there to help the new filter get colonised by bacteria as soon as possible
      The exception is the carbon filter, which needs to be replaced strictly on schedule because otherwise it just becomes ineffective.
  10. Carefully close the filter, pour the new water in the aquarium and replace the lights and the cover. Give your fish half an hour before turning the lights on again.

Should I Feed My Fish Before Or After Water Changes?

It is better to feed your fish before a water change, as that will allow you to syphon out any uneaten food. However, if you just didn’t remember they won’t mind being fed after a water change, however if your fish is very shy they may not eat well right after a water change.

When Should I Test Aquarium Water Parameters?

It is better to always test BEFORE you perform a water change, for various reasons. First of all, testing before a water change will tell you how much water you need to replace if, for example, you have an ammonia or nitrite problem. Secondly, the new water and the water conditioner are going to mess up your readings until they mix with the old water.

If you need to test the aquarium water after a water change just wait a few hours for everything to settle. If ammonia is your worry, get a 24/7 ammonia alert kit, which goes inside the aquarium stuck to the window. This way you can see any changes on ammonia levels when they happen. They also exist for pH.

Remember to test your tap water for nitrates and phosphates, and pH at the very least, as most water conditioners won’t affect those. You may need to invest in an RO unit in order to get suitable water for your aquarium, or choose fish that are naturally happy in a similar environment to what your tap water can provide.

Just in case, a reminder of how to test water parameters on your freshwater aquarium

What If My Fish Bite Me?

Most fish, including big ones, don’t have teeth and won’t feel inclined to eat you. They may nibble. Cichlids love to nibble on people’s fingers, and some fish such as Discus will even eat from their carer’s hands. Wearing aquarium gloves while doing maintenance is an option if you dislike the idea of fish biting you. However…

If you stock dangerous fish, such as piranhas or any other species who could bite or poison you, you will need to make sure they are out of the way while you perform tank maintenance. You can do this with a tank separator, to avoid having to fish them out and put them on a different tank.

Piranhas in particular have a worse reputation than they deserve, and many people take care of them without taking any extra precautions. It helps to wear aquarium rubber gloves and feed them a while beforehand, but still I would advice against risking your fingers while performing tank maintenance when a good tank separator will do just fine.

How Often Should I Change Aquarium Water?

The perfect maintenance routine will depend on your personal circumstances, your fish and how strong your filter is. HOWEVER, 25% a month should be a bare minimum. Most people aim for 10% to 20% per month, after the tank has cycled.

Some fish species, such as Malawi cichlids, require large groups to spread out agression and are messy eaters. This means you should consider doing 15% per week, or 30% every two weeks, at the very least. To reduce stress to fish, frequent water changes are better than large ones. A planted aquarium where plants use up Nitrates may require less maintenance that a bare-bottom one.

If you intend to breed and raise fry most fish will require nearly ideal water conditions. Many people do 5% water changes daily or every two days, depending on the type of fish. Some Discus breeders have the tanks wired to perform nearly continuous water changes to keep water chemistry perfect.

The best way to decide how frequently you need to change the water in your aquarium is by looking at the water chemistry. For example, while cycling an aquarium you should perform large water changes daily or every two days, to keep the ammonia levels as low as possible.

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