What Is The White Stuff Growing In Fish Tank Decoration?

Getting an aquarium and bringing home a new pet fish can always be dreamy and exciting. And when the excitement and dream are interfered with by a simple mistake then the heartbreak it follows can be unbearable. I have been through many situations while raising fish in the home aquarium. And one of the most problematic things about fishkeeping is the unwanted growth of various things inside the tank. One of them is the white stuff growing in the fish tank decorations. But what exactly is that White Stuff Growing In Fish Tank Decoration?

Well, the white stuff you and I are talking about can be anything ranging from bacteria to algae. These primitive living beings such as algae, fungi, or bacteria can give you a real headache when this stuff starts growing rapidly and cover all the fish tank decoration with white color.

I know white color is not always bad but hey think back properly what if it is something hazardous and causes real harm to your fish.

So, I am giving you a detailed article dedicated to explaining the white stuff growing in the fish tank decorations.

Let us dive in to know all about your problems and find solutions to them.

What Is The White Stuff Growing In Fish Tank Decoration?

You may panic when you start to see weird white stuff growing in the tank. And it is normal to panic when you stumble upon something you have never faced before.

Whitish stuff doesn’t invite itself into the tank and the reason behind it can be way harsh than you can imagine.

But first, let us learn what might be the white stuff that is growing in your fish tank decoration. You see there are many things or agents that might be the white stuff that is growing vigorously in the tank.

So, we have to come to the conclusion about what exactly is the white stuff you are seeing in your fish tank.


Now, the villain that no one can get rid of even when they want. Algae will always be there in the tank no matter what you do.

And you will face serious problems due to rapid algal growth when you mess up water parameters now and then.

The white stuff that might be growing in your tank is most probably a type of algae, white algae to be precise.

The white algae are quite rare but will grow rapidly and invade the aquarium once it gets the foothold.

These white algae are web-like and a slick film that will grow on the driftwood, rocks, and other decorations.

You might like to learn more about Algae in Fish Tank: Type, Cause and Control

If the white stuff growing in the tank is cotton-like, then there is a high chance you are dealing with fungus.

The improper water parameters invite fungus into the tank and thanks to dead and decaying matter, these primitive living beings will stay.

You can easily distinguish the fungus from other white stuff. And this fungal infection can transfer to fish in no time.

You will then be dealing with white stuff growing in your fish body rather than white stuff growing in the fish tank decorations.


During the various biological processes, many microbes get into the fish tank and most of them are not even harmful.

However, when the leftover food or even the metabolic activity intervenes the bacterial colony can grow bigger.

When the same water stays for a long time, the bacterial growth reaches its peak. And hence you will start to see white stuff growing in the fish tank decoration.

The white cotton-like stuff this time is exactly bacterial colonies that are growing rapidly in the fish tank.

Here is an article on Beneficial Bacteria In The Aquarium: What Are They And Is It Essential?

Why Is The White Stuff Growing In The Fish Tank Decoration?

Here we are after identifying the white stuff that is present in the aquarium decorations. But do these things appear out of the blue all of the sudden?

Well, no. There are various factors that contribute to the growth of these white stuff. And trust me, most of the causative agents start with your carelessness.

If you are careful enough and follow the fishkeeping rulebook, there is a thin chance of white stuff appearing.

However, knowing the causative agents might help to solve the problem. Let me make it easier for you.

Here is the list of the causative factors that fuel the algal bloom, fungal infestation, or bacterial bloom in the tank.

Improper Water Parameters

Most of the time, any problem related to fish keeping starts with improper water parameters. When one fails to maintain the ideal water parameters, it invites microbes and algae into the tank.

Unclear water, contaminated water, and malfunctioning of filtration system will invite algal bloom in the fish tank.

Microbe infestation follows when you are unable to take the water parameters back to normal or let that tank be on its own.

When the water temperature is more towards the warmer side, the algal bloom will be out of control. People often choose to keep an aquarium heater in the tank for their tropical fish.

However, this warmer climate will also

Too Much Lighting Or Sunlight

Oh, giving algae their ultimate source of energy, and what more do you expect? Algae thrive when there is more than enough lighting or direct sunlight reaching the tank water.

The tank placement and the use of improper light will not only invite algae into the tank but will make them stay.

The algal bloom once the sunlight hits the tank water will be uncontrollable and the white stuff you see growing now will cover the tank very soon.

Irregular Water Change

Water change plays an important role to balance the nutrient level and microbe growth in the tank. When you are careless about changing the water in the tank, you are inviting the white stuff to take over the fish tank.

I told you previously how your simple mistake or carelessness will lead to chaos you haven’t even imagine.

Improper Nutrient Levels

The dead matter, fish presence, or even the leftover food will raise the nutrient level in the tank for algae and microbes.

If the nutrients are too much in the tank, algae will so much food to eat and hence the rapid algal bloom.

Dead And Decaying Matters

The dead and decaying matters are the main carriers of nutrients that fungus and algae thrive on.

When these things are not removed immediately, the growth of microbes such as molds and fungi will reach the peak.

The dead and decayed matters are lifeless and hence it will be an easier target for parasites to thrive on. If you are late enough, you will be dealing with a whole tank full of the white stuff.

Avoid Overfeeding

When you start to give an adequate proportion of food to your fish, you will barely worry about the leftovers.

I know feeding your fish can be tricky and knowing the exact amount will give a real headache.

However, practice for a while and read the article I will give below to know more about feeding your fish.

Here is an article on Fish Food 101: A Beginner’s Guide On How To Feed Aquarium Fish

It is no rocket science to figure out the adequate portion and avoiding any extra food in the tank will definitely act as a miracle.

It is weird how people think feeding fish more will not create a problem. I can’t blame them; fish look so cute and adorable when they eat.

but that doesn’t give you a window to mess things up. Prepare good food for your fish and different food on alternative days.

This will help you as well as your fish living in captivity. Good food in the correct proportion will maintain the equilibrium of the aquarium ecosystem.

How To Get Rid Of White Stuff Growing In The Fish Tank Decoration?

When you know the culprit behind the chaos, it is easier to solve the case and come to a solution. You don’t have to be Sherlock to figure out the next step.

If you put your faith in me, I promise you will not regret your decision. it is easier to solve the problem when you work together.

The causative agents will give you hints of what you need to next to get rid of white stuff growing in the fish tank decoration.

I know minor things don’t catch much attention but those are the actual thing that you need to be more attentive about.

Let’s talk about the cure of the disease you are already facing in the fish tank. It is better to search for solutions rather than pinning and whining over them.

Performing Water Change

First of all, do an immediate water change in order to decrease the nutrient level. When you change the water from the aquarium, you will be diluting the nutrient content from the water.

The dilution process will automatically solve the microbial growth in the tank. After a while, you will start to see clear water with no white stuff growing in the fish tank decorations.

However, this one may control the growth of your fish but the real deal is to remove the prior white stuff too.

You need to scrape off the white stuff from the tank yourself before you perform the water. Once the water change is done, remember to filter out all the debris and the remaining part of the whitish growth.

You may underestimate the importance of water change in the tank but you cannot deny the fact of how helpful it can be.

With the water change, even the chance of ammonia poisoning and nitrite intoxication will be minimal. The preliminary treatment to every little water-related problem is water change.

But remember not to overdo aquarium water change or else you will have fish swimming upside down.

Removing White Stuff From The Fish Tank Decoration With Algae Scrubber

Your filter will not always remove the algae present in the tank. Actually, your aquarium filter cannot remove the algae as every alga is attached properly to the tank decoration.

So, the job comes down to you when it comes to removing the white stuff growing in the fish tank decoration.

But remember this step needs to be done after you transfer your fish or any other aquatic pet you have, into the next tank.

And, again, the water change might be necessary so that the algae cannot grow again after scraping it off.

How To Scrap Off The Algae From The Fish Tank Decorations?

Now, when your fish tank is free from living beings, it is time to get into the non-living things. You should now scrape off the algae from the glass, gravel, rocks, and other ornaments.

So, you might be wondering how to scrape the algae from the fish tank decorations. Let me help you so you don’t go picking rock or blade to do so.

I know picking off a razor blade or any other household items seems easier but the scratches these harsh materials will leave will be harder to remove.

So, you will need a specific scraper that is supposedly made to remove algae from the fish tank. There are many algae scrapers in the market and even on amazon.com, you can buy.

Aquarium scarpers and algae scrapers are completely different things and the price will vary highly when you research online.

So, when it comes to removing white stuff growing in the fish tank decorations, go for the algae scrapers or pads precisely.

These scrapers will neither disturb the ecosystem of your tank nor leave any scratches or breakage in your decorations.

Now, here is what you need to do. Take an algae scraper and scrape off the white stuff from the tank decorations one by one.

When you remove all the white stuff from the decorations completely, you need to rinse these decorations thoroughly with a power spray.

Once you are done with all the cleaning, put all the decorations in the tank one by one. Test the water chemistry and it is better to run the filtration system for a white too.

Performing Filtration

Sometimes, filtration will do the trick that other things can’t. The main reason for the white stuff growth in the tank is the failure of the filtration system.

The ammonia and nitrite level when gets higher from zero, then the growth of white stuff grows rapidly.

So, the filtration system with biological filter media housing beneficial bacteria will remove these toxins in no time.

The aquarium nitrogen cycle is the key to solving the unwanted growth problem in the tank.

When you deliberately remove these nutrients that serve the purpose of food to algae, fungus, and bacteria, then the growth will be null in no time.

This process will remove the white stuff as well as prevent the further growth of the white stuff in the fish tank.

Clean-Up Crew

When you can’t figure out what to do next, there is always an option of trying to clear the white algae with algae eaters.

This is the most beautiful way to make your tank clean and more attractive. The addition of another fish in the fish tank will definitely serve the purpose of beauty along with the solution to the existing problem.

But remember to check the compatibility of each fish with the fish pre-existing in the tank. There are other few aquatic animals such as snails that will even make the fish tank ecosystem complete.

It is quite up to you to make the decision between algae eaters. But whichever algae-eaters you choose, your problem with white stuff will be solved within few hours.

Now, let me give you names of few famous algae eaters that you can keep in your fish tank:

  1. Barbs
  2. Siamese algae eaters
  3. Chinese algae eaters
  4. American flagfish
  5. Danios
  6. Mollies
  7. Nerite snails
  8. Sun snails

Here is a detailed article on 30 Best Algae Eaters For Freshwater Aquarium

Maintain The Lighting

If your tank is placed in a well-lit area or the light you are using for the fish tank is high-powered, then it is time to change the lighting system.

You have to change the placement of the fish tank and keep it away from direct sunlight. Next, you have to purchase a light that is appropriate for a dim-lit tank.

If you do not want white algae growing all over the fish tank, then it is better to switch to the light that gives low output.

Once you change the tank lighting to a minimum, then the growth will automatically reduce to a minimum.

And after a while with algae scrapping and filtration, you will have a crystal clean tank with no white stuff growth issue.

Standardize The Nutrient Level

What happens when you stop giving food to your fish? They will die of starvation after a while.

The same thing will happen to the algae, fungus, and bacteria when you start to look eye on the nutrient level.

When you maintain the water chemistry back to normal or ideal, then the growth of these white stuff will go back to normal.

So, try every method to lower the ammonia, nitrite, as well as nitrate level from the fish tank.

When you maintain the water chemistry, the problem with unwanted growth of any algae or microbes will subside automatically.

How To Prevent Growth Of White Stuff In The Fish Tank Decoration?

Now, when you know the causative agents and the solutions to that problem, it is time to look at preventive measures.

I have been following the ‘Prevention is better than cure proverb since the very beginning of fishkeeping.

You see it is easier to prevent something from happening compared to clearing the mess after things go south.

I am not a big fan of thinking and worrying about solutions that’s why I try my best to prevent the problems from occurring in the first place.

I suggest you do the same as well. White stuff growing in the fish tank decoration might only be the starting phase of the problem and chaos you might have to face.

So, I will let you in on a secret that will help you prevent white stuff from growing in the fish tank decoration.

Here are the things you need to do if you don’t want to end up researching an easier way to get rid of the white stuff.

Regular Water Change

People often jokingly subside the idea of performing regular water changes in an appropriate and pre-planned schedule.

But boy how wrong are they. You can never imagine the impact of punctuality and regularity if you don’t start the habit yourself.

Regular water changes once every week will help you change 20 to 30 percent of dirty water that might be affecting your fish.

The fungus, bacteria, or algae grow and make the water unclear and dirty because of the toxins and decomposing matters present in the tank water.

Once you start to regularly change the water every week, there is a very low chance of having any of the problems.

Even lowering the ammonia from the aquarium water along with lowering the nitrite level will be way easier when you change the water once every week.

To be honest, you won’t have to face any of the problems when you are careful enough with the quality of water.

Proper Lighting Set-Up

When you plan to keep an aquarium at your home, you need to make sure you are taking of lighting as well.

As I have mentioned earlier, too much light will only fuel the algal growth in the tank, and trust me it is not a beautiful thing to watch.

If you set the proper lighting, dim lighting mostly, for your fish and in the fish tank, then the chance of absurd growth of algae is very low.

Proper Tank Placement

Sunlight is the main factor for the growth of fungus and algae in the tank. Your fish tank doesn’t do well when you keep it near direct sunlight.

Algae will get the fuel they need to grow rapidly in the fish tank. And the temperature fluctuation due to the circadian cycle will cause fungal growth.

When you pre-plan and place the fish tank away from the direct sunlight or too much lighting, you will be preventing the problem from occurring in the first place.

The white stuff growing in the fish tank decoration won’t even be the topic that will cross your mind if you are careful with the tank placement.

You might be interested to learn about Can I Keep An Aquarium On Balcony: Is It Really Possible?

Installation Of Good Quality Filter

The Aquarium Filtration method has a huge impact on deciding the things that will happen in your tank.

If you are careful enough with the filtration, then there will be a null problem in the tank.

A good quality filter will remove all the sources that will invite bacteria, fungus, or even algal growth in the tank.

Hikari sponge filters, AQUANEAT 4 and AQUANEAT are some filters you can choose from while setting up a tank.

Here is an article on Can I Turn off the Aquarium Filter at Night?

Removal Of Leftover Food

If you are attentive and careful enough while feeding your fish, you will not have this problem. But let bygones be bygones and let’s talk about the leftover food.

When your fish is full, it will almost immediately leave the food behind and start to swim another way. So, you have to fast enough to clean the remaining food from the substrate or gravel.

You can take help from the gravel cleaner that specifically serves the purpose of cleaning the tank.

When there is no leftover food, then the fungus and the bacteria will not intervene in the aquarium ecosystem.

Removal Of Dead And Decaying Matters

Once you see any o your fish dying or dead, it is better to remove the dead bodies almost immediately.

Dead bodies invite fungus and bacteria into the tank in order to help in the decomposition process.

You can imagine what will happen if you give quality food for fungus, algae, or bacteria in the tank.

The dead and decaying matters are the nutrients-enriched food for these prime causative agents.

So, if you really want to stop the white stuff growing in the fish tank decoration, don’t give food to the causative agents.

Frequently Asked Questions

Here are answers to some of the FAQs you might be wondering about. I have tried to answer a few to help you solve certain queries.

Will Vinegar Kill Algae In Fish Tank?

Oh yes, absolutely. Vinegar will help you get rid of the algae in the fish tank in no time. You might know how effective is vinegar when it comes to solving the dirty water and tank problem.

Have you ever used vinegar to clean the tank? If you have, great. And if you haven’t, you should give it a try.

Here is a detailed article on Can I Clean My Fish Tank With Vinegar: Easiest Way To Save Money

Trust me when I say this, vinegar can be an antidote to the problem related to algae. But do not use the concentrated vinegar, or else you will be solving another problem.

Distilled vinegar with 5 to 8 percent of acetic acid is a great one for cleaning the fish tank and getting rid of the algae.

This distilled vinegar will kill and stop the further growth of algae and also removes the stains from the tank.

The hard water deposits will also be subsided if you use this distilled vinegar to clean the fish tank.

So, yes, this multi-purpose vinegar will make your life easier while getting rid of the algae.

You might like to read more about Can You Use Vinegar To Lower pH In The Aquarium?

What Is The White Growth On My Fish?

There are many reasons for the white matter to grow in the body of your fish and trust me none of them are good things.

Firstly, look at the white stuff growing in the fish. What does it look like? If the white matter growing are like a spot on the body of the fish, then there is a high chance it is Ich.

You might be familiar with the white spot disease in the fish. The ciliate protozoan Ichthyophthirius multifiliis which acts as the parasite in fish causes the white spot disease.

The blister-like lesions on the skin and fins of the fish are the clear sign of Ich present in the tank. You need to take medicinal as well as natural solutions to the problem almost immediately.

Another reason that might be the culprit behind the white stuff growing in the fish can be a fungal infection.

Look at the mouth, skin, fins, or gills of the fish in the aquarium. If you see any cotton-like growth near these areas, then it is certain that your fish is struggling with fungal infection.

The fungal infection intervenes when you are unable to maintain the ideal water parameters in the fish tank.

Now, coming to the last but not the least reason for the white stuff growing in your fish body.

A viral disease namely, Lymphocystis, acts as the culprit in causing small yet many pin-prick-like growths in the fins, gills, or skin of fish that is white in color.

All of these things happen when you are not attentive or careful enough to look after your fish or the water parameters.


In conclusion, if you are careful enough in the first place, there will be no white, brown, or black stuff in the fish tank, decorations, or even in the fish. The wrong water parameters and your carelessness result in the growth of weird things in the tank. And these things will turn into something fatal in no time. However, the blame game will not give solutions to problems you have invited, so stay calm. With a calm mind, do every little thing you need to do and plan it thoroughly to make your tank a better place for fish to live in. You may struggle for a while but taking the right measures will help you get through it. Follow my instructions and the solutions I have listed above, and you will be solving simple problems in no time.

If you still have queries about anything I have missed out or mentioned above, then feel free to drop your question on the comment box below. I will try to get back to you as soon as possible.

Trust me, fishkeeping isn’t that hard as people make it sound and not as easy as some people contemplate it to be.

However, once you figure out what you are doing, you will do great in no time. Stay alert and careful. That’s the main motto here.

Good luck!!!

Happy Fishkeeping!!!

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