Last update: December 2, 2023

Indian Almond Leaves: Keeping your fish happy, naturally.

If you have been keeping fish for a while now, it’s highly likely you have heard of Indian almond leaves.

These leaves are often referred to as a natural miracle.

There are claims that Indian almond leaves are capable of bringing fish back from the brink of death, helping betta to spawn and even reduce stress in fish.

Do Indian leaves live up to the hype?

You’ll learn the answer to this question and more as I teach you everything you need to know about Indian almond leaves.

What are Indian almond leaves?

In aquarium use, Indian almond leaves refer to the dried leaves of the Terminalia catappa tree – a tree that is native to Southeast Asia and has been used in traditional medicine there for centuries.[1]

If you are wondering what a Terminalia catappa tree looks like, here it is…

Indian Almond Tree Terminalia Catappa on sandy beach in front of bay

The leaves are usually harvested by picking them up off the ground.

A single tree can drop a LOT of leaves…

Indian almond leaves on ground that are collected for aquarium use

Once dried, they are ready to be used in aquariums.

You might also hear Indian almond leaf shortened to IAL or referred to as catappa leaves, named after the tree it comes from.

Why are Indian almond leaves used in aquariums?

Let’s take a look at the 5 most common uses for Indian almond leaves.

1. Improve the quality of your aquarium water

Three Indian almond leaves sitting under water in aquarium improving water quality

When added to your aquarium, an Indian almond leaf will gradually break down. And as it does, it releases tannic acid, tannins and other substances into your aquarium.

As the tannic acid is released, it lowers the pH of your water. If you want a natural solution to reduce the pH levels in your aquarium, Indian almond leaf helps to achieve just that.

A study has also found that Indian almond leaves can significantly decrease water hardness (GH), which can benefit those who use hard water in their aquariums.[2]

Okay, but what good is that for your aquarium?

Well, the water out of your faucet probably doesn’t match the ideal conditions of the fish you keep.

Indian almond leaves change the water so that it more closely resembles the habitat of your fish, particularly those from Southeast Asia and South America.

Fish that benefit from Indian almond leaves include:

  • Angelfish
  • Barbs
  • Betta
  • Cory catfish
  • Discus
  • Gouramis
  • Killifish
  • Platies
  • Rasboras
  • Tetra

2. Natural medication for skin problems

Betta with ragged fins swimming next to Indian almond leaf
Image: Betta_Queen

Many aquarists swear by Indian almond leaf as a natural remedy for diseases or injury involving their fish’s skin or rather their scales.

It is believed the tannins released by Indian almond leaves kill bacteria, fungus and viruses, allowing an injured fish to heal much quicker.

It is even suggested that Indian almond leaf might be a better solution than antibiotics and other medications when fighting bacteria and fungus in commercial fish farms.[3]

In Southeast Asia, many betta keepers add an Indian almond leaf to their betta’s water because they believe that it toughens their fish’s skin and makes them better for fighting. They also use it to help a fish heal after a fight.[4]

While there have been no studies that prove Indian almond leaf helps toughen betta skin, there is strong anecdotal evidence to suggest it does.

The argument for Indian almond leaves as a medication for fish, however, is a little more compelling…

You see, Indian almond leaves contain flavonoids.

I won’t bore you with all the details, but a flavonoid is essentially what gives fruits and vegetables their color.

But it’s one flavonoid in particular that we are interested in – quercetin. And, Indian almond leaves have lots of it.

Quercetin has been shown to offer anti-inflammatory benefits to humans.[5]

Other studies show that tannins have anti-fungal properties.[6]

It’s possible the tannins and flavonoids in Indian almond leaves are responsible for fish healing faster.

3. A leafy location for your fish to spawn

Betta making bubble nest underneath Indian almond leaf that is floating on surface of aquarium

Many fish release their eggs (spawn) on or underneath fallen leaves. This helps hide eggs from predators or from washing away.

Discus and tetras prefer to spawn on leaves at the bottom of a waterway. Betta and gouramis, on the other hand, build bubble nests on leaves that float on the surface.

Indian almond leaves also have another benefit to spawning, and it’s one I covered earlier.

Many fish will only spawn under certain water conditions. And the reduced pH and water hardness may be exactly what is needed to trigger your fish to spawn.

4. Food and protection for fry (baby fish)

Indian almond leaves are the gift that keeps giving, even once your fish have hatched.

Many fish keepers add Indian almond leaves to fry tanks – an aquarium that is set aside just for baby fish.

First, the leaves give fry a place to hide, allowing them to feel safe. Sure, there are no predators in your fry tank, but your tiny fish don’t know that.

As the Indian almond leaves begin to break down, microorganisms called infusoria appear and feed on the leaf.

Infusoria are so small that humans can barely see them with our naked eye. However, to your fry that are barely bigger than an eyelash, infusoria might as well be a steak dinner.

Newly hatched fry happily chow down on infusoria until they grow large enough that they need to switch to an alternate food source.

5. A feast for your shrimp tank

Shrimp loooove Indian almond leaves. They often swarm any new leaf that is placed in their tank.

What’s the attraction?

Well, shrimp love the taste. Your shrimp will happily munch on Indian almond leaves and the microorganisms that grow on them as they break down.[7]

Shrimp also happily hide underneath the leaves once they are full. Dinner and a home? It doesn’t get much better than that!

Important: Some species of shrimp prefer high pH and water hardness. Indian almond leaves are not suitable for these shrimp.

As you see, Indian almond leaves benefit many different aquariums. Buy some here:

Dried Catappa Indian almond leaves ready for aquarium use

Why do Indian almond leaves change the color of your water?

As Indian almond leaves break down, they release tannins. These tannins can stain your water, turning it a yellow or brown tinge.

It’s similar to dipping a tea bag into a hot cup of water. The tannins are released into the water, giving the tea its color.

To a beginner, this yellow water can be quite a surprise.

I mean, whenever you go to a fish store or aquarium, the water is crystal clear, right?

Well, it might surprise you to learn that this yellow water is actually a good thing for many types of fish.

You see, lots of fish come from waters that are a murky brown color.

Most rivers and streams are a dark color because thousands or even millions of leaves have washed into the water and broken down.

While you might not be crazy about the color, this darker water may reduce stress in shy fish like discus.

And since stress is the number one cause of death in fish, a little bit of yellow water is a small price to pay for the happiness of your fish.

In fact, many fish owners prefer darker water – it allows them to create unusual and stunning aquariums like this one…

Blackwater aquarium with yellow water tinted by Indian almond leaves
Image: Nopy117

However, if the water gets too dark for your taste, don’t worry – I have the solution for you…

Activated carbon.

Activated carbon will do all the hard work for you. Depending on how much you use, activated carbon will either reduce the yellowness or clear it up altogether.

Be mindful that activated carbon will continue to absorb tannins until it is ‘full.’ When this happens, it needs to be replaced.

It is for this reason that I recommend buying a bottle of activated carbon like this one and using a filter media bag to hold it together. It’s much cheaper than constantly buying disposable filter cartridges.

Please note that completely removing the tannins will also stop Indian almond leaves from lowering your pH levels.[8]

If you want to keep the good stuff, a partial water change will help lighten your aquarium. The clear, fresh water will dilute the yellowness.

Why are Indian almond leaves recommended for betta tanks?

Betta hiding beneath Indian almond leaf at bottom of aquarium

Bettas are native to Laos, Cambodia, Thailand and Vietnam.

Their natural environment is slow-moving shallow water – like marshes or rice paddies.

If you have never seen a rice paddy before, it looks like this…

A rice paddy, the natural habitat of the betta fish

You see that water? Not exactly clear, is it? Habitats like these are referred to as blackwater – water that has turned dark due to decomposing leaf litter.

Blackwater habitats are typically acidic with very low water hardness.

Indian almond leaves help your water mimic these conditions – making your betta feel right at home in your aquarium.[9]

Bettas are commonly kept in smaller aquariums (even though they shouldn’t be!) – often by beginners who don’t know any better.

Because these small tanks can quickly turn unhealthy, the antifungal and antimicrobial properties of Indian almond leaves can help prevent diseases like fin rot.

Indian almond leaves also play a vital role in breeding bettas.

Because Indian almond leaves are broad, float well and don’t fall apart easily, they make a good starting point for a bubble nest.

The bubble nest underneath the leaf will prevent it from sinking even once it has soaked through.

If you have bred fish before, you know that fish eggs are notorious for developing Saprolegnia, a type of mold that grows under water. The antifungal properties of Indian almond leaves prevent this from happening.

Finally, once the baby bettas hatch, the infusoria that grow on the decaying leaf will be their first food.

As you see, Indian almond leaves play an important role in keeping your betta fish healthy, no matter how old he may be.

Some owners even use a clip, like this one, to make an Indian almond leaf into a natural betta hammock.

Check it out – a betta sleeping on his own leafy mattress!

Betta fish choosing Indian almond leaf over a hammock to sleep on

Which fish don’t like Indian almond leaves?

If your fish love high pH or hard water, Indian almond leaves are not suitable for your tank.

This includes most species of African cichlids – fish that are naturally found in more alkaline waters with a high hardness.

Why choose Indian almond leaves over another kind of leaf?

Amano shrimp eating Indian almond leaf that has mostly broken down in shrimp tank
Image: True_Panda

Well, Indian almond leaves are unique in that they break down slower than other leaves. The leaves have big, tough veins that take a long time to deteriorate, long after the rest of the leaf has broken down.

The advantage to this is that you can pull the leaf out of your aquarium without it disintegrating into small pieces.

Also, while other leaves might give off tannins, Indian almond leaves also have medicinal properties – something that other leaves don’t offer.

Important: Never place unknown leaves you find in your yard inside your aquarium. Not all tree leaves are aquarium-safe and may harm your fish.

How do you use Indian almond leaves?

So, you want to add Indian almond leaves to your aquarium?

The first thing you want to do is buy some Indian almond leaves. I find these or these to be the most consistent in quality. I have used both and happily recommend them.

However, if you are on a tight budget, then you can try these.

Now that you have your Indian almond leaves on hand, it’s time to add them to your aquarium. You can prepare Indian almond leaves in two different ways…

1. Dunking an Indian almond leaf in your tank

The most common way of using Indian almond leaves is to drop them directly into your tank. It’s generally recommended that you start with one medium-sized leaf for every 10 gallons of water inside your aquarium.

But before you do this, remove any activated carbon or Purigen from your filter. These two filter media will remove the tannins that Indian almond leaves give off, removing its benefits – it’s like running your AC with your windows and doors open.

Next, rinse the Indian almond leaf in fresh water to remove any leftover dirt or dust that may have been missed.

Now all that’s left to do is drop the leaves in your aquarium.

When you first add an Indian almond leaf to your tank, it will float on the surface. After a few days, it will waterlog and sink. Want the Indian almond leaf to sink sooner? Weigh it down with a rock or some gravel.

As for replacing, you can do so whenever you choose. It’s fine to let the leaves break down completely and remove the leftover veins – this can take up to two months.

If you have a smaller tank, you might find a single leaf is too much for your aquarium. You can either break the leaf in half or soak it in water for a few days. Pre-soaking Indian almond leaves in fresh water (use a water conditioner!) will release some of the tannins, resulting in a weaker effect when you place it in your aquarium.

The trick is to soak, not boil, your Indian almond leaf. Boiling can release the majority of the tannins, making the leaves less effective.

If it’s your first time using Indian almond leaves, make sure to monitor your aquarium water with an aquarium test kit to see how they react with your tank.

2. Make an Indian almond leaf extract

Maybe you don’t want to add Indian almond leaves to your tank because it clashes with your decor. Or maybe you just think they look ugly.

Whatever the reason, you will be pleased to know that you can receive the benefits of Indian almond leaves without actually adding them to your aquarium.

The solution?

Make an Indian almond extract.[10]

Simply boil about 2 quarts (2 liters) of water, place a medium-to-large Indian almond leaf in a clean jar and pour the hot water over it.

Let it stand overnight before removing the leaf. The liquid in the jar should be a dark brown color. You may notice small pieces of broken life floating in the jar – you can remove these with a sieve.

Cover the jar and store the extract in your fridge – it should last for several months.

Add this to your tank as needed. I suggest adding it every time you do a water change since freshwater dilutes the tannins in your tank.

Recommended dosing: 1 ounce (30 ml) of extract per 1 gallon (4 liters) of aquarium water

Add more or less according to your needs.

The advantage of using an extract is that no leaves will continue to break down, which prevents additional yellowing of your water. The extract allows you to precisely control the amount of tannins in your tank.

While making an extract is cheaper in the long run, it relies on being able to source high-quality Indian almond leaves.

If you can’t track any down or don’t want to go to the bother of making the extract yourself, buy it pre-made here:

Ocean Nutrition Betta SPA Black Water conditioner with Indian almond extract

Note: If your water has a high general hardness (GH) and carbonate hardness (KH), Indian almond leaf will have less effect on your parameters. The high mineral content of the water has a buffering effect and will somewhat counteract the acids coming from the Indian almond leaf.

If you live in an area where the water is so hard that you still feel soapy when you get out of the shower, you will see less change in your pH, GH and KH. But the antifungal and anti-inflammatory properties of Indian almond leaves still benefit your tank.

What if I use too many Indian almond leaves?

Did you add too many Indian almond leaves to your tank and now your pH is swinging like crazy?

Don’t panic!

Simply perform a 25% water change and add activated carbon to your water. This will filter out the remaining tannins, returning your water to normal.

I would be hesitant to do a larger water change than 25% – any more and you risk drastically altering your pH instantly, which can shock and kill your fish.

Instead, you want to rely on activated carbon to gradually remove the tannins.

Are there alternatives to Indian almond leaves?

Not feeling Indian almond leaves? Use these instead.

While the following alternatives may not have the same anecdotal medicinal benefits, they add tannins to your aquarium, soften the water and lower the pH.

1. Peat moss

Also known as sphagnum moss, peat moss can be put in filter media bags and placed inside your filter, hidden from view. You can find organic, chemical-free peat moss in the garden section of your hardware store. However, know that this will make your aquarium cloudy for the next day or so. I prefer peat moss pellets, like these, which don’t cause the same mess.

2. Alder cones

Alder cones look like mini pine cones. They come from the black alder tree that is native to Europe but is also grown in the United States. Alder cones are commonly used in shrimp tanks and for decoration. Buy them here.

3. Driftwood

In aquarium use, driftwood refers to basically any piece of wood that is safe to use in your fish tank. Because of this, there is a wide variety to choose from. Some are tannin-leaching machines while others barely tint your water. Driftwood should be boiled prior to use. Examples include cholla wood, which is a popular driftwood for smaller aquariums, while spider wood is popular in larger tanks.

4. Dried banana leaves

Dried banana leaves are much less common than Indian almond leaves but are used in a similar manner – in shrimp and betta tanks. Grab them here.

Indian Almond Leaves for Different Fish Species: Who Benefits the Most?

You know, there’s something almost magical about Indian almond leaves. Their versatility in providing benefits to various fish species in aquariums is truly remarkable. Let’s dive into which fish species reap the most benefits from these natural wonders.

First up, Betta fish. If there’s a poster child for Indian almond leaves, it’s the Betta. These vibrant warriors are native to environments similar to where Indian almond leaves originate, making the leaves an excellent addition to their tanks. How to use almond leaf for Betta? Simply add a piece of the leaf to the aquarium. The leaves not only mimic their natural habitat but also help prevent common ailments like fin rot and boost their vibrant colors.

But Bettas aren’t the only ones! Other Southeast Asian fish like Gouramis and Blackwater Tetras thrive with Indian almond leaves in their habitat. The leaves create a more authentic environment and aid in stress reduction – quite a relief for these often skittish fish.

Cichlids, especially those from the Amazon basin like Discus and Angelfish, also benefit significantly. The slight acidity and tannins released from the leaves help mimic their natural, acidic waters, promoting healthier, stress-free lives.

shutterstock 1337656538

Shrimp keepers, take note! Indian almond leaves are like a spa retreat for your shrimpy friends. They feed on the biofilm that grows on the decaying leaves, and the antibacterial properties of the leaves provide a healthy environment for them to flourish.

FAQs on Indian Almond Leaves

What are the main benefits of using Indian almond leaves in an aquarium?

Indian almond leaves are a natural wonder! They lower pH levels, add beneficial tannins, reduce stress in fish, combat fungal and bacterial issues, and provide a natural food source for some species.

How do I use Indian almond leaves in my aquarium?

Using Indian almond leaves is a breeze! Just drop a leaf or two into your tank. They’ll float for a few days, then sink and start releasing their goodness. You can also boil them to make a “tea” and add the water directly to your tank.

Can Indian almond leaves change the color of my aquarium water?

Yes, they can. As the leaves release tannins, your water might take on a light brown tint, mimicking the natural waters of a blackwater river. It’s all part of the natural vibe!

How often should I replace the Indian almond leaves in my tank?

Typically, a leaf will last about a month in your tank. Once it’s fully decomposed, it’s time to add a new one.

Are Indian almond leaves suitable for all aquariums?

They are fantastic for most, but if you have a species that prefers alkaline water, they might not be ideal. It’s always best to match your tank’s conditions with the needs of your aquatic pets.

Can I use Indian almond leaves for my Betta fish?

Absolutely! Indian almond leaves for Betta fish are a match made in heaven. They help in creating an environment that Bettas love, reducing their stress and boosting their immune system.

Is there a specific way to prepare almond leaf for aquarium use?

You can either add the leaf directly to your tank or boil it to make a concentrated tea. Both methods work great, depending on your preference and the needs of your tank.

Remember, folks, when it comes to aquariums, going natural is often the best way. Indian almond leaves are a simple, effective way to bring a slice of nature into your aquatic world.


Who knew a dried leaf could provide so many different benefits to your aquarium?

With careful use, you can use Indian almond leaves to recreate your fish’s natural habitat. Your fish will be happier for it!

Do you use Indian almond leaves in your aquarium? Let me know in the comments below!

Ian Sterling

Ian Sterling, founder of, began his aquarium journey over 30 years ago, driven by a deep fascination for fish and their diverse personalities. His website,, is dedicated to making fishkeeping accessible and enjoyable, offering beginner-friendly guidance, expert insights, and a community for aquarists to connect and share experiences.

Comments (60)

Nice post, Ian I think you have covered the Indian Almond Leaf very well. I use them all the time, in fact, I recommend everyone should have some. Except as you pointed out for high pH fish. Shrimp it is essential. Thanks.

Hi Robert,

Thanks for your feedback. I take it you use IAL in for shrimp?

It certainly is an unusual leaf. I would love to see a study done to determine what the actual medical benefits are.

Hi Ian

Many leave of trees and shrubs have medicinal properties. I did a quick search for any academic articles but did not come across any. API make Pimafix, West Indian bay leaf (pimenta racemosa) will treat fish fungal infections. One of the best leave for medical benefit is the Australian Tea Tree (Melaleuca alternifolia) it too is used in API Melafix. For humans, I always have a bottle as it is antiseptic, antiviral and antifungal. I sent many years in Australia and got to know it well. Trees have developed these properties to protect their leaves.


Very interesting,

It’s funny how few academic articles there are related to the hobby. While it’s fun that there is so much still left to discover, it does leave a lot of mean a lot of information passed around is based on anecdotal evidence – which makes it easy for misinformation and myths to establish themselves.

I had a look at your two suggestions. It doesn’t look like Australian tea tree is readily available for sale here in the United states, although you can buy the extract as an essential oil. West Indian Bay leaf is scarce and the few locations that did have it sold it at a higher price than Indian almond leaf.

It looks like for the tannin + medicinal combo, indian almond leaf is the way to go here in the US..

Melafix can damage a Betta’s labyrinth organ which is like a lung and make it hard or impossible for them to breathe air from the top. It should never be used in a Betta tank or with any other air breathers like Gouramis

I just found your blog and website, and I have spent the last couple of hours reading your articles and studying your reviews. I am especially interested in the use of these Indian almond leaves to lower the ph a little in my 20 gallon community tank (tetras, Cory cats, silver hatches, and a few nerite snails & an Amano Shrimp), Thanks for all the information that you have shared. Your articles are so well-written and easy to follow. I wish I had had your resources 6 years ago when I started fishkeeping.

Hi Lena,

Thanks so much for the lovely feedback. I actually started this site after my niece had difficulty researching the hobby and felt guilty constantly coming to me for advice. There is still soooooo much left for me to cover, I wish I had more free time to build it. I’m so glad that it has become a resource that is helping others 🙂

I would love to hear your experience with IAL. It takes a little bit of trial and error to figure how much to add to your tank at first, but once you have got a handle on it, you pretty much just repeat the same “dosage” each time.

Hello Ian
Juz read your blog. Nicely covered.
I have a question. I saw some fungus(cotton like covering) like growth covering IALs in my tanks. Is it okey or shall i remove them.

Hi Tauseef,

Is it white colored? This often happens when introducing things like driftwood, leaves and other botanicals. Take it out, wipe it away and place the leaves back in your tank. It generally goes away on it’s own, once it’s done feeding on whatever it wants. Look up images of “aquarium biofilm” if it looks like that, you have nothing to worry about – it’s normal!

Yes it is just the same. Thank you Ian. How many days old dried IAL can i add to tank? I have a female betta sorority tank 15gal. Trying my lvl best to keep it at its best(non planted). Coz i dont have any kit to test quality and ph of water. I juz do it by smell and color. 🙁

Hi Tauseef,

Unfortunately, this is only something you can tell yourself. Depending on the source and condition, some IAL contain more tannins than others. It’s trial and error. Unfortunately, without a test kit, it’s very difficult to determine what is happening in your tank.

Quite in depth and convincing argument for the use of Almond leaves. My first ‘amazon’ tank (30 years back!) I attempted peat for that black-water aesthetic. I wasn’t impressed, and my wife was less so!
I will probably try whole leaves, thanks for such a thorough article; I will be following your blog because it seems much more informative than most.

Hi Mykl,

Having used both, I probably wouldn’t use peat again either, it’s much more aggressive in it’s staining. Indian Almond Leaves are a little gentler in their approach. Thanks for the kind words, I would love to hear how your IAL experience goes in comparison!

Hi Ian

I just read your article and I find it very informative. I ordered some almond leaves and will begin to use them in my 125 gallon heckelii tank. The question I have is do I remove all carbon media for good?

Hi Chuck,

Excellent question! If you want to see the benefits of Indian almond leaves, and continue using them, then it’s recommended to skip the carbon. Activated carbon is a chemical media only removes bad smells, chlorine, medication and tannins(that the indian almond leaves give off). In an aclean, healthy tank, bad smells, chlorine and medication are not an issue anyway – carbon media isn’t essential to the functioning of a tank, although many brands would have you think otherwise.

Hi Ian,

Woukd like to check with you on the water that is used for making IAL EXTRACT, do we use tap water, or conditioned water which is chemically treated. And do we have to add aquarium salt as well? I have around 50 bettas which i only throw the leaves in. Am interested in making my own extract and see how it goes. Hope to hear from you soon

Hi Zac,

Any water you add to your tank should be dechlorinated. As for the aquarium salt, that’s unrelated to the IAL extract. It depends on what you are using it for.

I have 35 gallons tank with 4 Discus and 24 Neon tetras. Few days ago ph is goes to 7.6 and I use 3 Indian almond leaves. Now ph is come to 6.8
My questions are,
When I should remove the almond leaves ?
How I use the Filter because more Oxygen effects to raise the ph.

This article was very informative, thank you! I do have one question though…I have a 10 gallon tank with one bug eyed goldfish. I use bottled water and always condition it first. His tank has no issues except a super high Ph. I know they like a 7.6 but his is off the color chart. Can I use an almond leaf for him? I don’t really want to use chemicals so I’m looking for an alternative. I also do frequent water changes but it still stays high.


Hi Roxie,

Can I ask why you don’t use tap water? conditioned tap water is normally all that is needed for betta. Also, bottled water shouldn’t have a high pH that is off the chart. It would be like drinking ammonia otherwise. Are you sure your tests are working correctly? If the”off the chart” reading was accurate, your fish would probably already be dead.

Hello Roxie, sorry to but in but I while I didn’t use IAL in my daughters goldfish tank to lower the ph I did use it to treat a case of fin rot in one of the goldfish after much frustration and money wasted on meds that weren’t working… I had tried everything else and didn’t know anything but IAL that I hadn’t tried for the fin rot and in doing research I could find nothing specifically saying IAL was bad for goldfish so I went ahead and tried it. The goldfish is now in full recovery and growing back it’s fins nicely and as far as I can tell the IAL has had no negative effect on the goldfish so it should be safe to at least try but may I ask what test you are using? Because off the chart ph should already be killing your fish so if it’s not I’d be concerned the test is defective.

I have a 30 gallon community tank and found this article VERY informative and helpful (so much so that I keep sharing the link with anyone and everyone who has even one of the fish in the list of fish IAL benefits… I’m in several fish groups on Facebook and end up sharing the link at least once a day though usually a few times a day) I have to use store bought water in my tank unfortunately I live in one of my states largest eco disaster zones in history and to this day they are still working on cleaning it up. Look up velsico chemical plant ???? they tell us the tap water is safe but I used it when I first set my tank up and all my fish kept dying, stopped using tap water and they stopped dying… I personally refuse to drink my tap water because of this. Most of my fish are species from the list of fish IAL is good for and after reading this article I did more research on Blackwater aquariums and find I personally like the aesthetics of a Blackwater tank so the fact IAL has so many benefits for the majority of the fish I have I’ve been slowly working on converting my tank into a Blackwater Aquarium. Because I don’t want to dilute the tannins when I do water changes I’ve actually started pre treating my store bought jugs with IAL (just letting them soak and using a sieve when adding the water to my tank, and I always use water conditioner even with the store bought water.)

I should note I don’t always use store bought water (it gets expensive), sometimes I go a good distance away to another town where I’ll fill empty jugs from artesian well (free), that water however is very hard with a high ph so the combination of store bought water, artesian well water and IAL my ph still remains around 7.4

Hi Krystal,

Thank you for your support, it means the world to me!

I just had a quick read about Velscicol Chemical Company, that is horrifying! I can’t imagine how frustrating that must have been figuring out what was killing your fish. I can understand why you are refusing to drink the tap water. I hope they are eventually able to clean it up.

I really like your suggestion “pre-treating” the water with IAL, it’s a good alternative to making an Indian almond leaf extract.

Thanks so much for sharing! I hope the blackwater tank conversion goes well. I agree with you, I think the aesthetic looks beautiful.

Thank you for this informative article. I am googling to find out what tree is this thats sprouting in dozens where I planted. My friend gave me a bag full saying its called “poor man’s almond”. Well, I never found any almond by such name but by looking at the leaves I can identify it as the Indian almond given the fact that I live in India. My question is – can I plant this tree all around my fishery pond? Thanking you in anticipation.

Hi Asangla,

Unfortunately, I’m not much of a gardener, I won’t be much help here. I’m not sure what you have, so you’ll be want to careful that it is actually indian almond before planting it.

The almond is actually the seed of the tree. Its very small like a grain of rice and it does taste like a cashew nuts.

Hi Ian. Thank you for a very informative article!

I have some IAL, and was doing a bit more research on them as I have 2 poorly female bettas, and found your article… (Am yet to figure out what is going on… ????) have just added a couple of IAL to the tank (it’s a 34l that I’ve moved them in to for treatment of any kind). I fear it may be too late for these girls as the have been very good at hiding… a quick question though… the tank that they were in, also houses diamond head neon tetras and ottos… would it be an idea to add a couple of IAL to that tank for a while, just to be on the safe side…? Thank you in advance!!

Hi Liz,

Have you measured your tank with an aquarium test kit? (I recommend the API master test kit) This will let you know if there are any issues with water quality. I’d say about 90% of aquarium problems can be traced back to water quality. This could provide clues as to what is amiss.

IAL wouldn’t harm your other fish, you have little to lose by adding it.

Dear Mr. Ian,
Thank you very much for your informative page. Am new to Betta keeping so I learned a lot. IAL are common in my country (find them all over) so I’ve collected leaves cleaned added one to my Betta tank. He was a bit out of sorts prior, a day later was back to his old self which was a blessing.
My question is, how often do I change water after I’ve added IAL in to tank? Before I used to have a filter, change water once a week but now I can’t figure out should I keep changing like before or not.
Please help.
Thank you very much.

Hi Moshanthi,

If you have an abundance of leaves then I would suggest you keep doing your regular routine – it will keep your fishes water in the best possible condition if you are performing regular water changes. That’s awesome to hear that you have IAL so readily available though – we can only buy it in the shops.

Hi Ian,

That’s very useful information for the fishkeeper. Just a small point of clarification – that muddy water in the rice field you showed – that is not “blackwater” as you’ve described. Real blackwater is full of tannins, the color of rich black tea, and is importantly, crystal clear, without much sediment at all. The wild bettas in South-East Asia live in peat swamp forests, which have true blackwater. Images are easily found online.

Another interesting thing about Indian Almond leaves is that you can actually try to “supercharge” their effect by fermenting them. This allows them to partially break down, thereby “unlocking” the tannins and other chemicals in the raw leaf. The color of the fermented leaf is a rich dark brown and it smells like an expensive cigar. Quite easy to do – wash the leaves; soak them overnight in a solution of one tablespoon of sea salt to one litre of water (portion accordingly); retrieve the leaves (still wet) and stick them into an airtight container; leave for a week in a warm dark corner; string them up and dry them again out of direct sunlight. It’s exactly what is done for tobacco leaves for the cigar/cigarette industry, by the way.

That stuff above is what the Indonesian suppliers sell for a much higher price. If you have ready access to raw Indian Almond leaves (anyone living in the coastal tropics), you can try this fermentation trick.


Hi Jim,

Yep, you got me! I was weighing up whether or not to use that rice paddie photo – the stock image program I use doesn’t actually have any water like that. I crossed my fingers that no one would notice but I had no idea that so many experts would read my small blog too. So, well spotted!

That is awesome advice on how to ferment the leaves. I wish I had some on hand to try. Can I ask why they use sea salt in this process? Thanks for sharing your knowledge!

Hi Ian,

Good question about the salting of the initial water bath. I can only surmise that there are three broad reasons for doing so.

1) Slightly saline water helps accelerate the fermentation process;
2) Salinity helps to eliminate some of the potential bacteria, fungus, or other parasites that may be on the surface of the leaves. (Remember most of the time this is done with leaves just picked from the ground and given a quick wash);
3) In the context of Bettas and other species of fish which are less sensitive to salinity, that tiny bit of residual salt on the scrap of fermented leaf that you introduce into the tank actually helps a little – again to ward off fin fungus and external parasites. Your mileage will vary. I can say that my betta and anamo and cherry shrimp go absolutely crazy over fermented leaf.

Here’s a link to a nice video of how it’s done. Not my video, but very instructional. I think the source of the leaf is also critical- no pesticides, no vehicular fumes etc. I get mine from my workplace and from some offshore islands where there is very little human traffic.

Have a nice day,


Thanks so much for clarifying this Jim, I love to learn new things around the hobby.

What you say makes sense, especially around point 2. There would have to be some way to get rid of fungus spores and bacteria – you don’t really want that entering your tank.

I’m jealous that you have them readily available and can pick them up off the ground. The ones we purchase in America can vary dramatically in quality and size, depending on where you buy them.

Thanks again for sharing. My internet is being slow and won’t load the video but I will definitely check it out once I’m back up to speed!

Fermentation in the food industry is done with salt. It is called lacto fermtation. The addition of salt is to inhibit the growth of bad bacteria during the initial stages of fermentation where oxygen is still available, once all the oxygen is used up the lacto bacteria begin to do their work. It’s pretty standard to use salt for fermentations ????

Hi Dax,

Thanks so much for clarifying – that makes perfect sense for the food industry, to keep food safe. Interesting that non-edible fermented products use it too!

Hi Ian!

Just purchased a betta a few days ago. I’ve already read some articles about the benefits of IAL but dont know the exact proportion until I read your blog. I putted 1 medium IAL in a 3.8 L of water :(. And I dont know where I can buy activated carbon here in our province. There’s a lot of cattapa leaves here in our place but no activated carbon available 🙁

Hi Josephine,

No need to stress, a water change or two (don’t forget to treat the water before adding it) will reduce the tannins! You’ll need to balance this out with the rate that the Cattapa leaves leach the tannins out. I hope this helps!

Hi Ian, I am relatively new to the fish keeping world. I have a problem with the pH in my 80 gallon tank. I use water from a spring which is 7.4 when I add it to the tank with my weekly water change. However within 2 days the pH in my tank has risen to 8.0 I have been using pH Down to try and keep the water as close to 7.0 as possible. However I know this continual fluctuation is no good for my fish – mainly gouramis and tetras. I would like to try and go more natural in regards to lowering the pH and have been considering IAL. My question is; if the IAL kill bacteria would they harm the good nitrifying bacteria we all need in our aquariums?

Hi Lyn,

You don’t need to worry about the good bacteria, I have ran plenty of blackwater tanks, with lots of IAL and the beneficial bacteria isn’t impacted at all.

Hi Ian, I’m having a problem with IAL. I live in the tropics, due to room space limitation, my three bettas are in small tanks each measuring 15cm (L) x 7cm (B) x 20cm (H). I use a palm size IAL in each tank. After 2 days, there is a oily residue on top of the water and the water is choke full of clear slimy tendrils. This has happen a few times already and I have stop using IAL after the water change out of concern for my fishes. What’s happening here?

Hi Edmund,

Are your Indian Almond Leaves properly processed. Have you tried a different brand? I have heard of some that cause an oily residue but it is not expected – an IAL shouldn’t leave an oily residue in the tank.

It’s also possible that this is likely a tank size issue rather than a indian almond leaf issue. Any oil, no matter how small the amount, will be clearly visible in a tank of this size without any water movement.

Hi!! I know this is unrelated to the post, but I could not find a post on my question. Have you heard of/used tourmaline mineral balls in your tanks? If so, are they worth buying?


Hi! I put in the leaf and it never sank to the bottom and it grew mold in the leaf. Was it because I didn’t wash it before putting it in? Or what went wrong? Please help 🙁

Hi Gen,

Sometimes you need to encourage the leaf to sink. A pebble over the top will hold it down. And it’s usual for leafs to look “rotting” as they begin to break down.

Great info! Thanks for posting! I’m starting a 45G tank for live plants, tetras, rainbowfish, and hopefully a few loaches. I purchased Texas holey rock, which buffers water slightly. The gentleman at my local store said his water stays about 7.6 with the rock in. Would the holey rock cancel out the acidifying that catappa leaves do? The particular rainbowfish I’m looking at like 4.5-7.5 ph. Would it be wise to look for a different species?

Hi Elizabeth,

It all depend son your base level of pH. from your water and other acidification that occurs in your tank, the size of the rock etc. It’s hard to say the exact effect without testing it yourself. Also, fish prefer a stable pH rather than one that bounces around the range of 4.5-7.5. Im unsure how sensitive the fish you are looking at are, but a stable pH of 7.6 might suffice.

Hi Thet Ko Oo,

Unfortunately, the answer is “it depends” on your water, the size/quality of the leaves, the fish you keep, Kh, products used on the aquarium etc. This is a “trial and error” kind of thing – you’ll need to use an aquarium test kit to find the exact amount needed for your tanks.

Hi Mr. Ian,
Greetings of the day

I never new this before. Thanks for sharing such valuable information. Going to try is today itself.
Fortunately my neighbour owns an almond tree, I’ll use it and share my experience soon.

Thanks again for this.

Hi Anirudh,

You won’t get fresher than that. Just make sure you dry them before adding these leaves to your tank!

When you say I should get rid of the carbon filter, does that mean the black Sandy bag that goes into the sponge? I also have a bag with ceramic beads in it.

Hi Nicole,

The carbon filter is charcoal, it will look black and grainy. The ceramic beads should be kept in your filter at all times, that’s where your beneficial bacteria live which are essential to keeping your fish safe and why cycling your tank is so important.

Hello sir… do not mind of my comment… but i want to make a correction that betta also native fauna from Indonesia…

Vietnam, Cambodia and Laos maybe exist because Mekong River on it… but… the most famous betta is from Mahachai (Thai) and Riau (Indonesia)… the wild of them is crossbreed for a long time and become fancy betta nowadays…

Cattapa Leaf increase your betta or shrimp life… That is true… but as our habit keeping them… 1 leaf for half gallon they more happier… (usually we also use 2 of leaves for a small jar).. the problem is while the leaf decomposition, they are produce amonia…

but the fact… their antioxidan (from tannin itself) give betta immune of far water paramater…


Hi Sir,

Can you please suggest me some good or natural medicine for fish lice (argulus) for fresh water pond fish or any permanent solution for fish and shrimp argulus .and also good natural minerals ,probiotics and fish food if anything good available in the market. Thanks and awaiting for your reply.

Hi Raju,

I’m not sure where you are located, but if it’s only a few, you can remove them with tweezers. Otherwise, medication containing formalin is like a nuke. Be careful with it.

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