Betta Fish Water Turning Yellow? Do These

What is the first word that comes to your mind after seeing a fish tank with yellow water? Dirty, I guess. Well, anyone would think of that for sure. But what should you do if you see your Betta fish water turn yellow?

When Betta fish water turns yellow, the problem can be solved by changing the water. But that might not always be enough as you’ll have to use activated carbon and cure or boil the driftwood if it wasn’t cured earlier. Plus, using a good filter can also help with the issue.

Now the question is, why does this yellowness come in? And can you stop it before your tank looks like a yellow zombie land? Okay, let’s get you some answers on that.

Key Takeaways

  • The water can turn yellow due to released tannins from driftwood, rotten organic matter, excessive algae growth, and lack of filtration.
  • Getting rid of rotten elements, using a good filter, and partially changing the water can help reduce the water’s yellow color.
  • It’s possible to prevent the issue by using cured driftwood, proper feeding and filtration, high-quality substrate, and changing water regularly.
How To Clean Betta Fry Tank

Why Is Your Betta Fish Water Turning Yellow?

‘Why it’s happening’ always comes before ‘how to fix it’, doesn’t it? In the same way, if you jump into the solution of fixing the yellow water issue, know first why it’s happening so that you can prevent it from happening later.


Who doesn’t like driftwood in their tank? I bet you do, too. However, improperly cured driftwood can release tannins, giving your tank water an unwanted yellow/brown tan.

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Organic Matter

Your tank will accumulate decomposing organic matter, whether you want it or not. Yes, I’m talking about fish waste, uneaten food, and plant matter. All these matter release organic compounds that change your tank’s watercolor.

however the larger the aquarium is for your betta fish, the less frequently you have to do water changes


Not all, but some of the fish enthusiasts like having peat as their substrate. Sometimes, they even use it as filter media as it’s good at softening the water and lowering pH. As it releases organic compounds, the water turning yellow over time is nothing surprising.


Indeed, algae is a great source of food for some aquarium inhabitants. But if their growth is excessive, especially green and brown algae, you might quickly see a yellow tint in your tank water. After all, the pigments algae produce are quite helpful in making the water discolored.


There are a bunch of medications and treatments that come with elements that can change the color of water for a while. But as far as I’ve seen, they show no harmful side effects.

Tap Water

Have you been using tap water lately? If so, the water might get yellow as the tap water comes with dissolved minerals.

Less Filtration

If the filtration in your tank is inadequate, it will be tough to stop the buildup of organic debris. And you know what comes next. Exactly! Water discoloration.

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How to Fix the Yellow Water Issue?

You already know why it’s happening. Now it’s time to fix it. So, let’s start with –

Checking the Water Condition

Before you make any changes or adjustments, you need to know the current condition of your tank. Let’s call it the simplest way to determine what’s wrong with the water.

First, check the nitrate, nitrites, ammonia, and pH. Their level will say if your tank is dealing with a waste problem. If there’s any, a partial water change should be helpful.

Also, check out if you’ve got any floating debris around. If you see any, get rid of them. The same goes for anything like dead plants and uneaten foods.

Using Filter

If you want to keep your water colorless and clean simultaneously, I don’t think anything else can do that better than the right filter. You’ve already got one? Great! Now check if it’s working properly or not. Get it repaired if there’s a case of malfunctioning.

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Also, make sure the filter suits your tank. And if the water is still turning yellow, check the filter cartridge and clean it or change it if needed, especially when it’s been a while since you’ve had a new cartridge.

expert quote betta betta fish need clean water so filtration is essential

Rinsing the Substrate and Driftwood

If your tank is getting yellow because the driftwood is releasing tannins, don’t worry. They’re going to run out in the woods sooner or later. But if you don’t want to wait that long, you’ve got three options. One, remove the wood and cure or boil it; two, rinse it till the tannins go away, though it’s a bit time-consuming; and three, leave the wood in a bowl of warm water. 

By the way, it’s not always the wood that releases tannins; sometimes, the substrate can also do that. In that case, it’s better to rinse the substrate. It will at least lower the intensity of that yellowishness.

Changing the Water

Hold on a second! I’m not saying to replace all the water in the tank. Doing it partially should lower the yellowishness. But how much water am I talking about here?

Well, try to keep it around 40%. That should be enough to minimize the amount of waste the water contains.

Another good side of this is it’ll simultaneously lower the concentrations of nitrites and other toxins. But while doing this, ensure that new water matches the current water in the tank. Otherwise, the fish might get stressed.

my betta tank top view

How to Prevent the Water Discoloration Issue?

Prevention is always better than cure. So, if you don’t want to see your tank turn into a yellow pile of water, ensure you’re doing these in the first place.

Proper Use Driftwood

Cured driftwood assists in leaching out the tannins so that the water doesn’t lose its natural color. So, make sure that you’re using driftwood in your tank. But before putting it in your tank, don’t forget to boil or cure it properly.

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Quality Substrate

Do you know the best part of using high-quality substrates? They don’t release too much organic matter in the water, making it discolored. So, if you don’t want to see yellow water in your tank, use a good substrate.

Right Decorations

Before you drop your cash for decorations, make sure they don’t release unwanted dye that will change the color of the water. Plus, check out if they’re aquarium-safe or not.

Changing Water

Change the water regularly. This won’t let organic matter pile up; the same goes for other dissolved substances. Plus, it will save you from thorough cleaning every now and then.

my betta fish tank front view horizontal

Proper Feeding

Don’t even think about overfeeding. The more excess food you drop in the tank, the more uneaten food will accumulate there. All these foods will later on mess with the water quality and color.

Proper Filtration

Make sure the filter you’re using is perfect for your tank. Also, keep the filter media clean and maintain it regularly. If the filter works, you won’t have to worry much about removing impurities or maintaining water quality.

Use of Carbon

Try using activated carbon in your filter. It’s an effective way to absorb organic matter, preventing water from becoming yellow. But don’t forget to replace them regularly.

Controlling Algae Growth

It’s possible to control algae growth by controlling the duration and intensity of lighting. If you’re not keeping the lights on for a long time and are using algae eaters, keeping them within a limit shouldn’t be a problem.

Before We Go….

Do you know, along with color change, what Betta fish enthusiasts deal with often? The bad odor. But, like the yellowness of water, this can be fixed too. All you have to do is check my blog – Betta Fish Tank Smells Like Rotten Eggs: What To Do? The solutions are all here.

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Muntaseer Rahman

About Author

Hello, I’m Muntaseer Rahman, the owner of I’m passionate about aquarium pets like shrimps, snails, crabs, and crayfish. I’ve created this website to share my expertise and help you provide better care for these amazing pets.


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