How to disinfect a fish tank

Keep your fish happy and healthy by learning how to clean a fish tank, from the sand to the glass! These simple steps will have them swimming along happily in no time.

Updated 2 October 2023


AuthorBy Cleanipedia Team

Reading Time5 minutes

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As well as being easy to look after, fish can also be therapeutic, and children are bound to adore them. Knowing how to clean aquarium sand, glass, water and more will ensure that you keep your fish healthy, happy and most importantly – alive. Read on to discover our simple guide to the best way to clean a fish tank.

Key steps

  • Remove algae once a week using an algae pad.

  • Freshen fish tank water every two weeks.

  • Clean tank filters once a month.

  • Use diluted bleach to clean plants and decorations, ensuring you do so safely.

  • Use white vinegar to remove grime from the outside of the tank glass.

How to disinfect an aquarium: The important questions answered

Before you get started with our guide for how to clean an aquarium, make sure you know the answers to the most important questions.

How often should I clean my tank?

We recommend you follow our guide for how to disinfect a fish tank and clean your fish tank at least once every couple of weeks. To make the cleaning easier and more effective:

  • Clean your tank filter once a month.

  • Clean algae on the glass (without draining the tank) once a week.

Why should I clean my fish tank?

Fish need oxygen to live. The dirtier your tank gets, the less oxygen your fish is able to find and the more they’ll struggle to survive. In addition, algae can form. which uses up oxygen as it dies.

Do different fish and tanks need cleaning in specific ways?

Whilst you can use our guide below as a go-to for most of your fish tank cleaning needs; when you purchase specialist fish you should be given instructions, for example, for how to clean a tropical fish tank. Make sure you take these into account when you clean it out.

What temperature should my fish tank water be?

If you’re unsure about your specific fish you can ask a specialist, but in general:

  • Coldwater fish require temperatures of around 18 degrees Celsius.

  • Tropical fish require temperatures of 25 degrees Celsius.

  • Always use a thermometer to check the water temperature, rather than guessing by feel.

How to clean a fish tank: A simple step-by-step guide to cleaning each part

Cleaning your tank regularly is vital if you want to ensure your fish remain healthy. Read on for our simple guide for how to sanitise a fish tank from top to bottom.

You will need:

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  • How to clean and change fish tank water

    Did you know that changing all of the water at once can actually do more harm than good? A rapid change in living conditions can cause stress in your fish which could cause them to fall ill or even die. This is why a pet shop will always give you your new fish in a small amount of their own water. Here’s how to freshen up the water in your fish tank.

    1. 1

      If you clean your tank regularly, only around 15% of the water will need to be done each time.

      Forgotten to clean the tank for a while? Aim for around 25% of the water. If you’re not sure, don’t be afraid to ask a specialist for help and advice.

    2. 2

      Step 1:

      Use a manual siphon to change the water, removing the necessary amount into a bucket.

    3. 3

      Step 2:

      Dispose of the water.

    4. 4

      Step 3:

      Refill the bucket with clean water to the same level, ensuring the new water is brought up to the correct temperature.

  • How to remove algae from fish tank

    Cleaning algae from your tank is easy with the following two steps, all you need is an algae pad and stiff bristled brush.

    1. 1

      Use an algae pad to wipe any algae away from the inside of the tank.

      You can purchase these from most pet shops.

    2. 2

      Got some stubborn algae? Don’t worry.

      You can use a stiff bristled brush to gently scrub it away.

    3. 3

      Never use sharp instruments like razor blades.

      These could cause damage such as scratches, are dangerous in acrylic fish tanks, and could obviously cause harm to your fish if you choose to leave them in the tank during the cleaning process.

  • How to clean fish tank gravel

    Cleaning the gravel in your fish tank is essential to remove bacteria. This is a two-person job so be sure to ask a friend or family member to help.

    1. 1

      Hold your siphon hose

      approximately 1cm above the gravel.

    2. 2

      Gently run your fingers through the gravel

      to move them around.

    3. 3

      As the stones move,

      old food flakes and dirt will be dislodged and sucked up by the siphon.

How to disinfect aquarium plants and other decorations

It is easiest to clean plants and decorations by removing them from the tank.

Here are some safety precautions before you start:

Here’s how to clean and disinfect the plants and decorations:

  1. 1

    Mix a cleaning solution of 1-part Domestos Original Bleach to 9-parts warm water.

  2. 2

    Place the decorations into the mix to soak.

  3. 3

    For plants, dip a sponge into the mix and wipe down the leaves.

  4. 4

    Using hot, clean water, rinse off plants and decorations before returning them to the tank.

How to clean fish tank filter

There are a few different types of filter which could be used in your fish tank. Double check the manufacturer’s guidance found in your manual before cleaning. Here are a few simple notes to help:

How to clean fish tank glass

With the inside of your fish tank clean, it’s time to get the glass clean to ensure you can watch the fish and monitor their living conditions.

  1. 1

    Dip a clean cloth into white vinegar.

  2. 2

    Wipe this across the glass to remove dust, dirt and any grubby fingerprints or other marks.

  3. 3

    Allow this to dry naturally, and then buff with a cloth to remove any streaks and watermarks.

With this simple guide you now have everything you need to know about how to clean out a fish tank and keep your fish happy and healthy.

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