Cleaning and Maintaining a large Aquarium – Essential Guide

Taking care of your fish tank requires a bit of regular work, but your fish will thank you for providing them with a clean and happy home. This guide will walk you through all of the steps of a thorough cleaning. Your tank may not require all of these steps at the moment, but this thorough cleaning guide can be followed seasonally to ensure your tank remains grime free.

Although some of these steps (such as plant cleaning) don’t have to be performed often, it helps to know how to when the time comes. We’ll also cover more basic steps, like gravel vacuuming, that you’ll want to perform on a regular basis.

The Basics

Before you begin, let’s cover a couple of points that will help maintain the health of your tank.

When cleaning your aquarium, it’s best to leave the fish in place rather than removing them. Pulling fish from the tank puts unnecessary stress on them and runs the risk of injuring them during transit. You shouldn’t need to pull them during water changes, because you’ll be removing at most 25% of the water.

It shouldn’t be necessary at any point to fully drain your tank – in fact, it’s strongly discouraged. Completely fresh water will remove the beneficial bacteria and reset your nitrogen cycle from scratch, which is something that could kill your fish. Adequate cleaning and a partial water change should be plenty to remedy even the dirtiest of tanks.

For regular cleaning, you can also leave any plants or decorations in place. Only when they become visibly dirty or covered in algae should they be removed, and even then they need to be cleaned using a specific process (something we’ll cover later in this guide).

Finally, never use any type of soap to clean any part of the tank, even if it’s thoroughly rinsed off. The residue left behind (even if it’s not enough to see) can kill your fish.

Regular Cleaning

To perform regular cleaning, you’ll want to start by scraping algae off the sides of the tank. An algae scraper is the best tool for this job, and you’ll want to use a plastic (rather than metal) scraper if your tank is acrylic.

With the sides scraped clean, it’s time to move to the gravel. You’ll want to use a siphon to vacuum the gravel clean. This takes care of two tasks at once, as you can use the siphon to remove water as you clean in preparation for your partial water change.

With the gravel clean, continue using the siphon until the desired amount of water is removed. For weekly cleanings, you’ll be aiming for 10% to 15% of the water – for more thorough cleanings, you’ll want 25% to 30% of it gone. Remember to keep at least half of the water in order to maintain adequate beneficial bacteria levels.

When done, simply top the tank off with fresh water that has already had the chlorine removed using a conditioning treatment. This is the only time you should add water to the tank. Resist the urge to refill water lost due to evaporation between cleanings. It may seem like a good idea, but topping off without removing a portion of the old water will increase the dissolved mineral content of your solution. Over time, this can create an environment that will eventually be unsuitable for aquatic life.

Cleaning Plants, Rocks, and Decorations

Occasionally, you may wish to clean the (non-fish) contents of your tank. Remove them from the tank and scrub under running water. You can use your algae scraper if that makes the process easier. Never use any type of soap.

If the residue is more stubborn, mix a solution of 5% bleach and 95% water in a new bucket that has never been used for any other task (to prevent contamination). Let it soak for 5 minutes, then thoroughly rinse off and allow to air dry before returning to the tank. You can even use this solution to clean living plants, if necessary.

Cleaning the Glass

If you need to clean the glass or any other clear components, such as lights, make sure not to use any commercial or household glass cleaners. These products contain strong chemicals that are highly toxic to fish.

Instead, use a straight vinegar solution, which will remove deposits without introducing harmful chemicals to your tank.


If you follow this guide, you will greatly reduce the odds of harming your fish in the process of cleaning their tank. Remember not to use any cleaners unless they are specifically listed as safe for aquarium use. With ongoing maintenance, you shouldn’t need to thoroughly clean your tank very often. Weekly cleaning can go a long way towards eliminating residue build-up.

Here you can see a good fish tank maintenance schedule. Read more about it: The Aquarium Water Care Guide.


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