How to Clean a Fish Tank: Mind the Water

Christy Caplan
Teenage girl cleaning fish tank

If you have fish, then you need to know how to clean a fish tank. Any fish keeper will tell you that it takes some elbow grease for a fish tank to look attractive. Learn about the necessary cleaning supplies and how to clean a fish tank in seven steps. You'll also find some fish tank cleaning hacks, so your aquarium doesn't turn into a swamp.

How to Clean a Fish Tank in Seven Easy Steps

For general maintenance, there are seven essential steps to cleaning your fish tank properly. Yet, how often should you clean the tank? Is this a daily or weekly task?

  • The rule of thumb is to clean a fish tank once a week.
  • Three areas to focus on are the water freshness, the tank bottom, and the amount of good bacteria you have in the tank ecosystem.

This step-by-step overview will help new fish keepers clean a fish tank.

Cleaning Equipment Checklist

You'll need a list of cleaning supplies to get you started. This list isn't meant to overwhelm a new fish keeper, as these tools will be used each week to keep the tank sparkling.

  • Rubber gloves
  • Clean water
  • Clean container
  • A temporary fish tank
  • Fish net
  • Large bucket for waste
  • Siphon gravel vacuum
  • Algae scraper pad (try a magnetic algae cleaner)
  • Aquarium glass cleaner
  • Razor blade
  • Clean towel or cloth
  • Water testing kit
  • Thermometer
  • pH meter

Step 1: Unplug the Equipment

Unplug all equipment in the tank. This should include your heater, filter, and pumps. Next, grab your rubber gloves to complete the cleaning.

Step 2: Remove the Fish and Artificial Plants

Fill a secondary fish tank with some of the existing (used) aquarium water and place the fish and artificial plants in there while you clean the main tank. Remember that moving fish (especially tropical fish) can be stressful. Handle them with care.

  • Use the fish net to transfer your fish carefully to their temporary clean container.
  • The water in the temporary tank should come from the original water in the aquarium.
  • Don't forget to remove decorations and never move live plants.
  • One tip to ensure you don't overclean is to remove only 50 percent of the decorations so that beneficial bacteria stays in the tank.
Hands Cleaning Fish Tank

Step 3: Vacuum the Tank

For this step, you'll use a gravel vacuum and fish tank siphon. Gravel cleaning is important to remove extra waste and food. Use your siphon gravel vacuum with an attached hose to remove the water and gravel. Here's where your waste bucket comes in handy.

  • The rule of thumb is to not remove more than 40 percent of the water in the tank. The goal is to keep the beneficial bacteria in the tank.
  • Debris will rise into the siphon; continue this until the water starts to clear, or you have cleaned all of the gravel floor sections.
  • A gravel vacuum is designed to churn the gravel around in a column of moving water to loosen and carry off debris trapped in the gravel in the tank.
Cleaning of gravel in a freshwater aquarium

Step 4: Remove Algae

Next, you'll use the scraper pad to get rid of the algae.

  • The scraper pad and razor blade will help remove algae build-up on the aquarium glass.
  • Use a pad or clean cloth to clean tank decorations.
  • Use the aquarium glass cleaner to remove any smudges on the glass.
  • The easiest way to clean the glass in your tank is to use a magnetic algae cleaner or a soft toothbrush.
  • Never use soap!
Cleaning algae using a scraper

Step 5: Clean the Filter

You must wash the filter cartridge every week, so adding this task to your weekly tank cleaning process makes this easy. A sponge filter is a common type of filter. The filter must be rinsed in the original water removed from the tank.

Step 6: Reassemble

Put back the plants, decorations, and replace the water.

  • Always take the tank's temperature with the thermometer and collect water at the same temperature before you start to refill it.
  • Plug all the equipment back in and put back the plants you removed.
  • Use purified water to refill the tank as it helps control algae growth.
  • After the water is replaced, carefully place your fish back in the tank using the fish net.
taking tank's temperature

Step 7: Use At-Home Test Kits

The last step is where you'll want to use the water testing kit. Using at-home test kits inform fish keepers about the pH, temperature, salinity, nitrates, and ammonia to maintain your fish's health. All of these factors should be in the optimal range to keep healthy fish.

  • Test kits measure the four most important water quality levels in a fish tank quickly including pH, high range pH, ammonia, nitrite, and nitrate. High levels of ammonia and nitrates are poisonous to fish.
  • They come with glass test tubes, a holding tub for easy storage, and a step-by-step instruction booklet with a color chart that provides information on how to correct unsafe water conditions.
  • Fill each of the tubes with 5 ml of water from the tank. Each bottle in the kit has instructions that explain how many drops to use in the test tube and whether to shake the bottle before testing the water quality.
  • Each test tube will need to be inverted after drops are added to ensure the water is properly mixed. Then, hold up the test tubes next to the test kit color chart provided with the booklet.
  • The chart helps determine what areas need to be addressed and whether your fish tank is ready for prime time.
Teenager using a water chemical test kit

Tank Cleaning Hacks

These are not shortcuts, but they are ways to ensure your tank stays clean and the school of fish remains healthy.

  • Place live plants to help keep the water clean.

  • Use filters to help circulate the water and remove debris as well as creating surfaces for good bacteria.

  • It is important to keep the water clean but not sterile.

  • Add fish breeds that are great tank cleaners such as Cory Catfish.

Avoid Over Cleaning

Some people change their water more than they need to. Over-cleaning or changing the water too frequently can disrupt the perfect balance, and there is a wealth of bacteria that live in your tank. With a small tank, you need to change the water more often than you do with a big one, as waste can build up much more quickly.

Also, if you take everything out and wash it with chlorinated water or bleach, this kills the bacteria. One tip is to remove 50 percent of the tank decorations so not all the beneficial bacteria is removed during weekly cleanings. The rule of thumb is don't overclean, establish a routine, and stick to it,

A Healthy Tank Equals Happy Fish

Cleaning a fish tank should be efficient and stress-free. The goal is to keep your fish colonies safe when cleaning this 'biosphere,' and you don't want to shock these sensitive animals. Remember that the more fish you have, the more waste you'll have. Following these seven easy steps will take the stress out of cleaning your fish tank.

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How to Clean a Fish Tank: Mind the Water