My bathroom smells like fish: How to fix

You are home after a long day at work and you can smell something fishy coming from the bathroom. Your first thought might be that there is a leak somewhere in your house, but after inspecting it thoroughly you find nothing. You might be wondering what is causing this strange fishy smell in your bathroom. 


If you find yourself asking “why does my bathroom smell like fish?”, the following explanations may enlighten you. There are many reasons why your toilet or bathroom smells like fish. From an old or poorly ventilated septic tank to rotten food, there are many causes for this unpleasant odor. In most cases, these smells are harmless and will go away after some time. However, if the fishy odor persists for more than a few days and begins to interfere with your life, it’s best to get it checked out by a professional plumber as soon as possible.

What Causes The Bathroom To Smell Like Fish?

First, let’s take a look at what causes the bathroom to smell like fish in the first place. Bathrooms are notorious for developing an unpleasant smell. There are many reasons for this, but the main culprit is bacteria. When the air around the bathroom is moist, bacteria grow and multiply really quickly. Bacteria are responsible for the smell of your bathroom because they cause a reaction with oxygen that results in the production of Hydrogen Sulfide, which is the chemical that gives off the foul smell. 

Old or poorly maintained septic tanks

If you live in a rural area, you might have a septic system instead of a city sewage system. First off, let’s talk about the old or poorly maintained septic tanks, which are known to cause the bathroom to smell like fish. A septic tank is a containment unit that is used to treat sewage by breaking it down with bacteria. If the septic system is old, or if it has not been properly maintained, then the tank could be full of solids and sludge.

This causes the tank to become a breeding ground for bacteria and mold that can cause the bathroom to smell like fish. The septic tank has a drain pipe attached to it that runs outside the house. The pipe’s job is to remove the sewage from the tank by flowing it out of the house. If the pipe is blocked, then it can’t do its job, which can cause a foul smell to emanate from the bathroom.

Rotting food

The next cause of a fishy bathroom smell is rotting food. Have you ever left some food out for too long and forgotten about it? If so, it may have rotted and caused your bathroom to smell like fish. Well, not just your bathroom, but the entire house. Bathrooms are small and do not get fresh air as often as other rooms in the house.

This means that the smells are more likely to accumulate and stay there for longer than in other rooms. Rotting food, no matter where it is, can cause a smelly and unpleasant atmosphere in the house. You can look next to the toilet or under the mats to make sure that nothing was left.

Bacterial growth or mildew

Bacterial growth or mildew is another cause of bathroom smells like fish. When the humidity in the bathroom is too high, bacteria can grow and cause a bad smell. Bathrooms are normally humid, even in dry weather, because they contain water and moisture. When the humidity is high, it is a prime breeding ground for mildew, which can cause a fishy smell in the bathroom.

Mildew is a type of fungus that grows on almost all surfaces in the bathroom, including walls, floors, and even in the bathtub. It can be seen as a blue-green or black fungus that appears in wet, humid conditions. If you find mildew in your bathroom, it is best to clean it immediately because it can cause issues if not dealt with in a timely fashion.

Urine smell

Finally, let’s take a look at the cause of the bathroom smelling like fish is urine smell. If you have small animals or children in your house, then it’s possible that they might have urinated in your bathroom.  

Even though urine is mostly water, it can smell really bad if it’s in a small space like the bathroom. Most of the time, it’s possible to remove the smell by opening a window and leaving the room to air out, but if it’s been there for a while, you might need to get a professional to take care of it.

Why does my shower smell like fish?

The bathroom isn’t the only room in the house that can smell like fish. If you notice that your shower smells like fish, then it is probably a sign that there is a leak in your plumbing drain. If there is a leak in your shower, it can cause the water to mix with the bacteria inside the pipes, creating the stinky smell that we all know too well. There are a few ways to fix this problem. You can buy a cleaner that will take care of it for you, or you can do it yourself with a few simple steps. If your shower has a drain at the bottom of it, it might also be clogged with hair and other debris. If this is the case, you’ll need to clean it out before you can unclog the drain.

A plumber can use a drain camera to check what is going on. With this tool it is quite easy to find and fix possible problems. 


Bacteria are responsible for the smell of your bathroom because they cause a reaction with oxygen that results in the production of Hydrogen Sulfide, which is the chemical that gives off the foul smell. Bathrooms have a lot of moisture in them, which facilitates the growth of bacteria. If you’re wondering why does my bathroom smell like fish?, then you should know that there are many reasons for this. The best way to prevent this smell is to keep your bathroom clean and well ventilated.