Do you notice a bad smell coming from your fish tank? It could mean there’s a problem with your aquarium.
A well-maintained aquarium should not have any bad odor.
There are many reasons that can cause a bad odor from your aquarium.
Here, I’ll talk about why your aquarium might smell bad and how you can fix it. There are a few common reasons why it might stink.
But before we get into that, let’s think about what good-smelling water in your aquarium should be like.
What does good aquarium water smell like?
In a healthily maintained aquarium, the water should have a very faint odor. I would describe this scent as earthy, similar to a clear pond or stream.
Many fish keepers describe that a healthy tank smells like freshly tilled soil.
I absolutely agree with this. If you have already owned several aquariums, you know what I mean.
The aroma of an aquarium is usually not noticeable unless we are very close to it. It is a definitely fresh, natural scent. Sometimes slightly sweet or musty but not unpleasant.
The water must not smell bad at all. If it smells like something is rotting or like sulfur, there could be issues with the tank or the water itself.
Regular maintenance, filter cleaning and water changes are key to maintaining a healthy aquarium.
Why does my fish tank smell?
There could be a few reasons why your fish tank smells bad, like a dirty filter, dead fish, or rotting plant pieces.
Sometimes, the water’s balance might be off. But you need to figure out what’s causing the stink first before fixing it.
Causes of bad smells
Below I present to you the 7 most popular reasons why your aquarium water stink.
Dead Fish
This is actually the main cause of the bad smell in your aquarium. If you notice a stinky odor, it could be because your fish have died.
Rotting fish stinks and fills the room with a terrible smell. Of course, if you have a covered tank, you may not notice this smell.
If the tank is open, you will quickly smell the dead fish.
If your fish tank has too many plants, it might be hard to see a problem.
But if there are fewer plants, it’s easier to see if any fish have died, and you can take them out quickly.
As part of aquarium maintenance, it is always worth counting your fish to make sure that all of them are healthy.
Some fish like to hide during the day and only come out at night. The red tail shark and pleco are examples of such fish.
Days may pass and you won’t notice that your fish is gone. It’s worth knowing where your fish spends its time.
The decomposing body will emit a more intense odor.
If there are any fish missing from your fish tank, it can start to smell bad. So, it’s a good idea to check your tank regularly. Make sure to look behind each rock, decoration, or plant to see if any fish are hiding or have gone missing.
Also remember that some fish may jump out of the tank. They can also cause an unpleasant odor. At first you may think that it is a smell coming from the water.
A fish taken out of water will not survive and will quickly start to stink. It is always worth checking behind aquarium stand or nearby furniture to see if there are any dead fish.
Getting rid of the unpleasant smell left by a dead fish is quite simple. If you remove the fish, the smell should disappear soon.
Dead fish smell bad, but that’s natural. Fish don’t live forever, so it’s impossible to stop this smell entirely.
The only thing you can do is take proper care of your aquarium so that your fish live as long as possible.
Rotting plants
Rooting plants in your aquarium might sometimes make a bad smell. But this doesn’t happen as often as other causes.
Rooting plants are easy to spot. They often have a slimy brown or black color. You will know by their appearance that they need to be removed from the aquarium.
Dead plants can also affect the quality of your water. The more plants decay in the aquarium, the greater the chance that the water will start to stink.
Remember that algae can also rot. They leave a terrible smell of longing scars. Particular specifics will not your aquarium smell in case of blue green algae .
To keep your plants healthy, you need to prove that the water has the right ingredients.
Healthy plants don’t give off bad smells.
Provide your plants with adequate light and nutrients and this will contribute to good plant growth.
Some snails, like Malaysian trumpet snails , devour dead or rotting plant parts. It is worth having them in your aquarium.
Dirty filter
A dirty filter can sometimes make your aquarium water smell bad.
Stuff that’s left on the bottom of the tank can get pulled into the filter.
If you don’t clean the filter regularly, the gunk in it can start to rot. This is especially true for the mechanical filter, which catches floating bits in the water.
Therefore, remember to remove dead fish, uneaten food remains and rotting plants from the aquarium.
So, it’s important to take out any dead fish, leftover food, or decaying plants from the tank. Cleaning the filter should be part of your regular maintenance routine.
When you’re changing the water, it’s a good idea to rinse the mechanical filters to get rid of extra gunk.
Also, check if the water is flowing properly through the filter. If it’s not flowing well, bacteria won’t be able to break down ammonia properly, which can make your tank smell bad.
Overfeeding
In order for the fish to develop well, we must, of course, feed them every day. However, overfeeding is one of the worst things you can do to your fish.
Your fish ate a certain amount of food in one feeding. The remaining uneaten food sinks to the bottom and begins to rot.
Decomposing food causes an unpleasant odor. The more food accumulates at the bottom, the stronger the smell becomes.
In addition, decaying food may affect the level of nitrites, and it will certainly do so unless we remove excessive amounts of food first.
To avoid the rest of the food in the aquarium, feed them only as much as they can eat in one session. The fish should eat the food within 2-3 minutes.
Of course, the exact time may vary slightly depending on the species of fish and the type of fish food.
If you accidentally pour in too much food, you should immediately remove the remains using a vacuum cleaner.
Regular water changes are the best way to prevent unpleasant odors.
Fish poop
It’s not surprising that fish poop can make your tank smelly, just like human poop smells bad.
If you maintain the tank properly, you shouldn’t have any problems with bad smells.
Feces remaining in the aquarium may cause a bad odor and may affect the parameters of your water.
Of course, the more fish we have, the more poop there will be in the aquarium.
Certain fish, like gouramis and goldfish, produce a lot of poop, so you’ll need to clean more often if you have them
In such cases, only by changing the water regularly you can avoid the unpleasant smell.
Make sure you don’t have too many fish for your tank size – that’s a common mistake for new fish owners.
Overcrowding is a common problem for beginner fish keepers. You can use a calculator to figure out how many fish your tank can handle.
If your tank is overcrowded, the only thing you can do is increase the frequency of your maintenance routine.
You’ll have to change the water more often and clean up the tank more frequently
Of course, you can always buy a larger tank or simply remove some of the fish.
Gravel or substrate
Do you smell rotten eggs from your aquarium? It is very likely that the substrate may be the cause.
Uncleaned fish poop or leftover food may gets stuck between the grains of gravel, sand and rocks, where they continue to break down.
If the substrate is particularly thick and left for some time, it may cause the oxygen in these places to be consumed.
This may lead to the formation of zones where there is no oxygen. In such conditions, anaerobic bacteria develop and can cause the formation of unpleasant gases.
The formation of this gas may be associated with bad smell of rotten eggs.
To stop the bad smell from coming out of the ground, just make sure to clean it regularly.
When you change the water, it’s helpful to use a special vacuum cleaner to suck up hidden trash.
Mixing up the ground can also help to avoid anaerobic zones where there’s not enough oxygen.
Some snails or fish like loaches can help turn the gravel.
Before choosing a substrate for your aquarium, consider and read how to properly care for it. This will help you prevent unpleasant odors.
Water Conditioner
Believe that water conditioner can also affect the unpleasant smell from your aquarium.
When opening the bottle with the conditioner, you probably noticed that it does not necessarily have a good smell.
When I open Sachem Prime, I immediately feel the eggy smell coming from the bottle.
Many conditioners have sulfur compounds that make a bad smell.
Using too much conditioner can make the water smell bad in your tank. If that happens, you need to change the water.
It’s better to use less conditioner than too much.
You can also choose a conditioner that has been developed so that it does not emit an unpleasant odor.
Additionally, consider choosing a conditioner that’s designed to not produce a bad smell.
How to remove bad smells?
The important thing is that before you start step by step, you must first identify the cause of bad smell. Once you know, get rid of that first. Usually, removing the cause of the smell is the key.
Nevertheless, it is worth taking steps that will ensure that your aquarium will be healthy and fresh.
So what steps should you take?
- Clean your tank
- Changes 20% of the water each day
- Add activated carbon to the filter
When it comes to cleaning your tank, I mean performing treatments like:
- Cleaning the glass
- Vacuuming the substrate
- Cleaning of all decorations
- Conjuring up the filter inlet and outlet
- Cleaning the filter
- Removing any dead plants and fish
- Changing the water
We should perform the above activities regularly to prevent unpleasant odor.
For the next few days, it’s good to change 20% of the water each day. Adding fresh water and moving the water slowly will help get rid of some of the bad smell.
It is also worth adding activated carbon or a carbon filter that will stop bad odors.
The carbon filter will effectively remove bad smells and make the water cleaner by removing discoloration. It can also help remove toxins from the water column.
This is just a quick fix because if you don’t get rid of what’s causing the bad smell, even activated carbon won’t fix it.
Plus, remember, you have to change activated carbon often. Its effectiveness isn’t that great.
It may happen that after cleaning the tank, it will smell even worse. This usually happens if you haven’t done maintenance for a while.
To avoid this, you need to stick to a regular maintenance schedule.
In conclusion
If you finish reading this whole article, I believe you’ll come to one main point.
Taking care of your aquarium regularly is like a blueprint for keeping bad smells away.
Bad smells typically happen when organic stuff starts to decay.
However, if you remove it regularly and it does not start to accumulate, you will not have problems with bad smell.
It’s a good idea to create a regular schedule for maintenance. It’s crucial to delineate tasks to be performed daily and those to be done monthly for optimal results.
This is the best solution to prevent bad smells.
If you have any other tips for removing bad smells, let me know in the comments.
