How to Clean Out a Freshwater Fish Tank Properly

How often you clean out your fish tank will somewhat depend in the number calling the tank home. The type of aquarium can also dictate as to how often you will need to clean it. As a fish owner, chances are you have observed your tank over time and built up your own routine based upon the requirements of your tank and fish. For newbie fish owners, keep your eye on the aquarium, you will see the tank become dirty and will then know it is time for a clean. Don’t panic if you misjudged the length of time without a clean, follow the steps below to have your aquarium gleaming and your fish happy in their spring-cleaned abode.

Table of Contents

What Do I Need to Clean Out My Aquarium?

Unchlorinated water (in the quantity you need to replace)
Gravel vacuum
Filter replacement equipment
Algae pad
Plastic razor blade
Aquarium-safe glass cleaner

Do I Need to Move My Fish to Clean the Tank?

There is no short answer when it comes to this commonly asked question and opinions differ immensely. Many people with smaller tanks tend to move their fish due to ease, but many comment it is also less stressful for the fish to work safely around them. Most owners with large aquariums often keep their fish in the tank due to ample room. Really, it comes down to your fish and your personal preference and neither is right or wrong.

How Much Water Do I Need to Change?

If you have happy, healthy fish based upon your current cleaning schedule, you should only need to remove 10-20% of the water. If any of your fish look unwell, you’ll want to change between 25% and 50% of the water. If you have had any fish pass away, 50% is ideal.

How Do I Clean the Tank Inside?

This step can be completed before or after you remove the water you will be replacing. Reach for an algae pad and get scrubbing the plastic or glass surfaces inside the tank. You can wear rubber gloves as long as they haven’t been treated with or used to handle chemicals. It is imperative to use a brand-new algae pad. Scrubbers and spongers used in your kitchen will not be appropriate.

If you have any stubborn spots of algae inside that won’t budge, get your hands on a plastic razor and gently use this to scrap the grime off.

How Do I Clean the Outside of the Tank?

Fish owners have two options when it comes to cleaning the outside of their fish tank. You can either use a purpose-made aquarium glass cleaner, or a vinegar-based solution. Never use regular cleaning products, these contain chemical or cause fumes which can hurt your fish. Don’t forget to wipe down all areas of the tank, including hood, light and tank top.

How Do I Remove Tank Water?

The safest way to remove old tank water is to use a siphon. Make sure you have a large bucket nearby as the siphon will suck water from the tank and this will need to be deposited. Make sure you use a non-battery-operated siphon and be very mindful of any fish in your tank if this is how you prefer to undertake cleaning duties.

Also, make sure the bucket you use is dedicated to fish cleaning only. Do not re-use buckets for other pets or laundry.

How Do I Clean the Gravel at the Bottom of the Aquarium?

Your siphon can also double up as a vacuum cleaner. Simply edge the vacuum siphon attachment along the gravel. You will notice the siphon pick up debris from the gravel. If you like to keep your fish in the tank whilst you clean, place a section of fishnet tights over the end of the vacuum to act as a guard and prevent your fish from getting vacuumed up too.

This technique can also be used when wanting to clean any decorations within the tank. Simply run the vacuum along the surface of any object to remove dirt.

How Do I Add the Fresh Water?

You will need to replace the water you removed with fresh, unchlorinated water which is the same temperature as the water in the aquarium. You can use a thermometer to gauge this. It is important that temperatures are monitored as even slightly lukewarm water is too hot for most types of fish. Usually, your tank water is around room temperature.

If you are using tap water, you have two options to rid the water of metals and toxins:

Add a drop of Decleor
Leave the water in a container overnight and uncovered; this will cause the chlorine to evaporate and the water to become room temperature

When Should I Change the Filter?

You should change the carbon inside your filter cartridge once a month. Changing it does not affect the biological filtration and not doing so can greatly affect your fishes’ health. It is also best practice to rinse the filter off once a week to get rid of minor debris.