Does a Fish Tank or Aquarium Smell – The Only True Answer

This is a question people often ask me, and it’s super easy to check. But when you don’t have an aquarium yourself, how can you know whether they smell or not? Well, here is the answer given by me and many other aquarium owners.

Does an aquarium smell?

It’s not possible to smell an aquarium when you’re in the same room because they do not create an overpowering odor. If you purposely smell the aquarium close to the water surface, you’ll be able to smell it. Bad odor is an indicator your tank needs maintenance.

Now that you know the short answer, you must know there are some things you can do to minimize the smell coming from your aquarium. It’s also important to know what precautions you should take in your room when looking to buy a fish tank.

What does a fish tank smell like?

It’s difficult to give an accurate description of what an aquarium smells like. Each tank is different, and it’s based on how well the aquarium is maintained. When talking about my fish tank, I can tell you the smell is only noticeable when I put my head directly above the tank and purposely smell it.

It does not smell foul, rotten or like ammonia or sulfur. Instead, I would describe the smell of my aquarium like slightly fishy with other earthy notes.

The fishiness comes from the beneficial bacteria that are housed in my aquarium and help keep my tank safe for my fish. I would further describe the earthiness as freshly tilted soil in the garden.

The slight smell that comes of a healthy freshwater aquarium is not pungent nor unpleasant.

How to minimize the smell produced by an aquarium

Under no circumstances should you be able to smell an aquarium when you’re in the same room. However, the aquarium water is filled with living things and other organic matter, that inevitably produce odor.

Keep the top of the aquarium clean. The biggest tip I can give you is to try and stay on top of your maintenance, and make sure you do it in the right way. If your aquarium is going to have a lid, you must keep everything under that lid clean.

You’re potentially keeping plants, and you will be dealing with algae at some point. If you leave some of them to dry under the bright lights that are in your lid, they will start to smell. Therefore, it’s important to remove anything that’s left lying under the lid of your tank.

I’m for sure guilty of “temporarily” putting some plants on the piece of support glass when I’m doing maintenance. When you forget to remove anything, the chance that you’re able to smell your tank increases.

Male hand cleaning aquarium using magnetic cleaner.

Keep your room well ventilated. If you’re keeping an aquarium, water will evaporate, that’s just a fact. If your room is not ventilated properly, the humidity increases. If you’ve ever been to a humid place, it’s no pleasure sitting in a room.

Therefore, I recommend opening a window regularly. I’m keeping my aquarium in my bedroom, and when I’m gone for a weekend I do feel the urge to open a window to get rid of some musty aquarium air.

Stay on top of your water changes. When you’re a fish keeper, you’ll know that your fish produce waste. That’s nature: they poop. If you’re also keeping plants or other critters, you’ll have to deal with even more waste.

It’s pretty simple to remove this, by taking out a percentage of water (often 25%) and replacing this with new water. This way, all the toxins in the aquarium water don’t have a chance to gradually build up over time. In a poorly maintained aquarium critters may die.

Dead fish, plants or snail are able to rot in your aquarium, producing ammonia. If you’ve cleaned anything with ammonia before you’ll know that this stuff smells! If your aquarium starts smelling of sulfur or ammonia, you know you need to put some more effort in cleaning your tank.

How to get rid on an existing smell in a fish tank

If you’ve found yourself with a bit of a smelly-aquarium problem, you don’t have to worry. Obviously, an aquarium will smell a bit, but when the odor becomes noticeable in the air around your tank, it’s time for some action.

Clean the top of your aquarium. It’s critical to remove any and all organic leftovers that are stuck to the glass on the inside of your tank. This is the primary source of musty smell in your aquarium.

If that’s clean and you’re still smelling your tank, try performing a 40% water change where you focus on removing any detritus and organic matter from your tank. This will remove any ammonia sources and at the same time reduce your nitrates.

If there are still smelly particles in your aquarium water that make it murky and unpleasant, there still is a great trick up our sleeves.

Feeding aquarium fish with dry large food

Adding Activated Carbon to your filter. Activated carbon is available for fish tanks and on the market by many different brands. The truth is, it does not really matter which one you buy. The active carbon will remove any chemicals from the tank and will make your aquarium noticeably more bearable within days.

The activated carbon does not last indefinitely because it looses its power. I would recommend changing it every month, but some brands even recommend 2 weeks. This can get expensive quickly, but adding it for one run will already reduce the odors coming from your tank.

It will also make your aquarium water clearer, which is something many people try to achieve. Activated carbon truly is the best way.

Do some fish smell more than others?

If your tank is well maintained, there will be no difference between different aquarium fish when it comes to the produced smell. However, there is a major difference between how messy fish are.

A goldfish is known to be very messy. They eat a lot and therefore poop a lot. These fish will require more maintenance than other aquarium fish in the hobby that are less messy.

When you fail to adjust the amount of maintenance based on what fish you’re keeping, fish that produce more waste will smell more due to the increase ammonia, nitrite and nitrate that’s dissolved in the aquarium water.

Bart Sprenkels

I have been keeping multiple aquariums since I was 18 years old. Just like many of you, I started with two goldfish but quickly learned they were not suitable for aquariums. Later, I switched to a tropical community tank and I also have two pet musk-turtles in a bigger aquarium. You can read more about me here.

Recent Content