How to Clean a Five Gallon Fish Tank

Are your fish about ready to pack up and move to cleaner waters? Afraid of cleaning the tank because the last time you did it, the fish had clean water, but died from the shock of it all? Make your fish tank shine and your fish happy with this simple procedure!


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    Decide how much water you will replace and prepare that much replacement water in a clean container. Add dechlorinator according to the package instructions. You can buy dechlorinator at any pet store. Testing kits for other water in the tank, if at all possible. Used correctly, the aquarium siphon will not harm them. do not remove the fish from the aquarium, it will stress them and they will die.
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    If you have a buildup of algae on tank walls, then use an aquarium sponge or clean, soap-free cloth to clean it off. Some people leave this alone, as it is preferable to green water and provides food for many fish, but it's best to remove at least some of the algae. Removing plankton from green water requires an old or expensive filter.
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    NEVER change your filter cartridge. It houses all the good bacteria that is the heart of the aquarium, and removing it all will kill your fish. Only replace it when it is falling apart, and when you do so, keep the old cartridge in the tank until the new one has grown good bacteria. .
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    Use an aquarium vacuum/siphon to suck out a maximum of 25% of the tank water. If possible, though, keep up with water changes and change only 15% of the water per week. This rate can climb as high as one third per day in persistent, threatening turbidity. Push the end of the vacuum down into the gravel and move it around. Aim for any visible debris. Generally, the vacuum will take up the debris and the gravel will fall back to the bottom.
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    Rinse decorative items (plants, rocks, etc.) that were in the tank with clean, room temperature water if they appear to need it.
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    Scrub the tank with a new sponge, towel, or other type of cleaning cloth (be sure that whatever you use is free of any soap or cleaning fluids (make sure no residuals by rubbing and rinsing thoroughly). In fact it is best never to let anything near your tank that has ever been near soap or detergents.


  • DO NOT use soap. Soap kills fish fast.
  • Live plants cost a bit more than their plastic counterparts, but they can help to keep the aquarium chemistry balanced and healthy.
  • The most important part of cleaning the tank is keeping the water temperature constant. Fish die, usually, from the shock of going from warm to cold water.
  • Consider getting your tank a cleaning crew. Shrimp are natural cleaners, eating algae, dropped food, and other debris, plus they're fun to watch. Various bottom-feeding fish perform similar roles. Snails also scavenge, but they can be a bit messy and some types can reproduce prolifically. These critters won't do your job for you, but they can help keep the tank healthy in between cleanings. Ask at a good pet or aquarium store or look them up online.
  • Avoid putting too many fish or fish that are too large in a small tank. They will crowd each other and produce waste too quickly.
  • Frequent, small water changes are better for your fish than infrequent, large ones, since abrupt changes in water chemistry or temperature can shock fish.
  • You can pick up a plastic tank siphon at any pet shop or even a discount store.
  • Rinse everything that is going back in to the tank completely, to remove any algae, slime, etc.
  • Act fast, as the fish in the bowl are running out of air. If they are breathing air from the surface constantly, put the air hose in the bowl.
  • Change carbon according to the instructions (or don't even use it at all), since old carbon can leak poisons back into the tank.
  • Do not overfeed your fish. 1 flake per fish, per day. It's bad for the fish and excess, uneaten food can contribute to the production of harmful ammonia.
  • Put the fish into small plastic airtight bags half filled with old tank water when taking them out to clean the tank. When you've cleaned it, float the bags with the fish in them in the tank for 15-20 minutes. This will ensure that the water temperature is the same in both the bag and the tank.


  • Do not attempt to move a full fish tank. Nothing special should remain in water. That much water is very heavy and the seams could fail. Move it two weeks before your next scheduled change of filter, and dump about four fifths of it.
  • Never use cleaners, soap, or chemicals to clean your fish tank, and use an unused cloth/sponge. They will remain on the tank, and get into the water--and then you can kiss your fish bye-bye. Even one drop is enough to kill.

Things You'll Need

  • A gravel vacuum or siphon.
  • An empty bucket for wastewater.
  • A clean container or two, thoroughly rinsed.
  • A tank-safe scrubber, free of chemical additives. Look for one at a pet store.
  • Dechlorinator.
  • Aquarium net.

Article Info

Categories: Aquarium Maintenance and Repair