5 Tips on How to Clean a Fish Tank Without Removing the Fish

Detergent, chlorine, and other cleaning solutions can be harmful, even deadly, to the aquarium inhabitants. Due to this, many aquarists don’t know they can learn how to clean a fish tank without removing the fish.

Sure, keeping your fish out of the tank during the cleaning process is the safest method. If you are always able to remove the aquarium inhabitants and don’t find it a hassle, this might not be the right article for you.

However, if, for any reason, you find it challenging to keep your fish outside of the aquarium when it’s cleaning time, you’re in the right place!

I’ll teach you how to clean a fish tank without removing the fish and give you a few general cleaning tips. 

Let’s get started!

Do You Have to Empty a Fish Tank to Clean It?

The easiest way to clean your tank is to remove the fish living inside of it. However, you don’t need to do that. Quite the opposite – I would advise you against removing the fish from the tank, unless in urgent situations or for breeding purposes.

For example, you might want to put your fish into a 40-gallon breeding tank when you want them to reproduce.

Fish go through a lot of stress when you move them, even though this might make the process easier for you. Or, rather, you think this makes everything easier. The truth is much different.

Once you understand how to clean a fish tank without removing the fish the right way, you’ll find this to be the easiest method ever!

Where to Put Fish when Cleaning a Tank?

While you might think it doesn’t really matter where you put fish when cleaning the tank, this isn’t the case. You need to think really hard about finding the right tank, even if just for a short while. 

The tank in question must be fully prepared for its inhabitants. This means it has to have a heater, an air pump, and a filter. Also, it should be fully cycled, which can take a while.

As you can see already, it’s much easier to simply have your fish stay inside their old tank during the cleaning process! Especially as this is something that you should do twice a month, if not even more often.

But how to do that safely?

How to Clean a Fish Tank Without Removing the Fish?

You might think that cleaning a tank always involves a cleaning solution and rubbing a cloth all over the tank’s glass. 

While this might be a good method to keep your tank glass crystal clean, this isn’t a proper way to clean the water and the rest of the tank. 

Below are a few things you need to do if you want to properly clean a fish tank without removing even a single fish from it:

1. Water Changing

Regular water changing is the best way to make sure your tank is clean all the time. No, I don’t mean changing all of the water.

Change about 10% of water each week. If your tank is particularly large, replace a greater amount of water – 15 – 20% will do. 

Some owners like to change up to 30% of their water weekly. However, unless you have a really dirty tank, I think this can do more harm to good. Only replace such a great percentage if you keep shrimp, and even then be careful not to change the water parameters.

Changing only this amount of water is enough to ensure your water stays clean without disrupting the water quality.

Of course, you need to make sure the replacement water has the same parameters as the water already inside the tank. Otherwise, you’re doing more harm than good.

2. Filter Cleaning

While the filter cleans your tank, it requires cleaning itself. 

In general, you need to clean your filter media once a month, if not more often. The best timing would be to pair the filter cleaning with replacing the water and completing other cleaning steps. 

Don’t go overboard. By cleaning your filter just enough to make sure it works properly, you’ll ensure there is still some aerobic bacteria left while removing the anaerobic bacteria. Yes, these two are not the same.

3. Plant Bleaching

Yes, you’ve read that correctly. You need to bleach your aquarium plants from time to time.

You can use bleach to dip your aquarium plants. You need to make a solution consisting of one part bleach and 19 parts water and dip plants in it for a few minutes.

As long as you rinse them thoroughly after bleaching, they’ll be safe for your fish.

If you are afraid to use bleach, use vinegar. However, be careful as vinegar might be even more dangerous than bleach, as it can disrupt the pH levels of the water. 

In fact, I prefer using bleach to vinegar, as it’s much more efficient and the solution is so mild that mistakes are less likely to happen.

4. Algae Scraping

You also need to clean excess algae from your tank. 

Most of the time, algae will build up on the tank wall or decorations, creating an ugly, green layer.

Sometimes, you can find limescale next to algae. This is a white film located on the edge of the water level. It is an indication of hard water.

Algae can be easily removed with a scraper or a razor, as long as you are careful not to damage the glass. 

Many store-bought scrapers come with instructions, so they are pretty straightforward to use.

Another solution is vinegar, but only use it on the aquarium cover and areas where it won’t get into the water.

You might also use a kitchen sponge to remove less persistent algae spots. Make sure you use a clean sponge that hasn’t been contaminated.

Luckily, there are a few ways to keep algae from forming. The biggest mistake you’re probably making is keeping your tank in inadequate light.

While lighting is important for most fish species, you don’t want to give them too much light. Sure, this will help them look good, but it might stress them out. Not just that, but it will increase the reproduction rate of algae.

Fortunately, a smaller amount of algae isn’t harmful. Quite the opposite – many animals, such as the blue pearl shrimp and most snail species, love eating algae and biofilm. Still, you don’t want to have too much of it. 

5. Substrate Vacuuming

Just like your floor is likely the dirtiest place inside your home, the substrate is the dirtiest part of your tank. Any debris and junk will fall down to the bottom of the tank.

And just like you would vacuum your home, you need to vacuum your substrate.

Fortunately, thanks to modern technology, this isn’t a challenging task. All you’ll need is a gravel siphon kit you can find in most larger pet supply stores.

Using a gravel siphon kit is not just easy, but it is much more beneficial compared to removing all the substrate and replacing it. This is because substrate is also a home of good bacteria that keep your tank healthy. 

There are also other tools, such as an under gravel filter or an air pump, that can help you clean your substrate. However, unless your substrate is really dirty, they are not necessary.

Bottom Line

Now you know that it’s possible to clean an aquarium with fish still in it. In fact, it’s the preferred cleaning method of most experts!

Removing the fish from the tank will stress them out, and it’ll add a few extra steps to this otherwise straightforward process.

As long as you don’t use any chemicals, your aquatic pets will be safe. They probably won’t even realize that they’re in the middle of algae scraping or substrate vacuuming!

By learning how to clean a fish tank without removing the fish, you’ve dealt with one of the most daunting parts of having an aquarium. Nothing can stop you now!