Catappa leaves or Indian almond leaves are very popular in the aquarium world and are used for a variety of purposes. Many breeders swear by using indian almond leaves for their bettas, and I have been using them ever since I tried them for the first time. But why exactly are they useful for betta fish and do they even work as claimed by so many aquarists?

What are Indian almond leaves or catappa leaves?

Terminalia catappa L. is a tree which spreads from Africa and upper Australia to the whole of South eastern Asia and can grow over 115 ft tall. 

The leaves from these trees are called catappa leaves, from their scientific name T. catappa. The most commonly used name is Indian almond leaves, because the fruits taste like almond. Leaves can get from 5 inches to upwards of 15 inches for big leaves.

Catappa leaves for betta fish
Leaves and fruits of T. catappa.
Catappa leaves in nature.

Trees shed leaves twice a year and the leaves can be harvested by simply picking them up from the ground. Before falling off, the leaves turn purple/orange.

The quality of the leaves is determined by factors such as substrate, lighting and processing. That’s why it is important to buy your leaves from a reputable seller (scroll to buying catappa leaves). Unless you are lucky to be able to collect them yourself. They can only be used dried. After a quick rinse you can use the dried leaves.

When trees shed their leaves, the leaves dry up and end up in rivers and water systems. This causes the water to become brown and more importantly add the useful tannins which are beneficial for your fish. So if you see any brown water in habitats it isn’t polluted, it’s a sign there are a lots of tannins and fallen leaves in the water.

History of usage

Indian almond leaves have been used by local people for decades before they entered our aquarium trade. The beneficial effects of the leaves on betta fish were first discovered by local Betta breeders and betta-gamblers. People bet on what betta fish would win and mostly, both fish would be seperated heavily wounded (fights were usually stopped before death). Catappa leaves were then used to heal the wounds of the fish and prevent further possible infections/diseases. The leaves are also used for conditioning and spawning as well as permanent addition to the water.

The big leaves have been used for a long time in traditional medicines, for example to fight liver cancer. If it really works as a human medicine is unsure.

Why are Indian almond leaves beneficial?

By putting catappa leaves or extract in your water, the leaves let go of several substances.
Because the leaves are so rich in chemical composition, some of those chemicals released into your water have positive effects on the health of your betta fish. Some well-known chemicals in catappa leaves are alkaloids, flavonoids, saponins, tannins and steroids.

The effects of saponins are somewhat debatable but out of former research it has been stated that low amounts of saponins have positive effects on some fish like carp and perch.
About other chemicals such as flavonoids it has been stated that they have improved reproduction, antibacterial and growth-rate.

It has also been claimed by some that tannins in catappa leaves have metal-binding and anti-toxicity capabilities.

Fighting diseases/illness

Many aquarists add catappa leaves to the water when their fish is sick or add it in combination with other medication. But they are also great for prevention of many diseases. I find that when I add catappa leaves to my water my fish become less shy and more lively. I believe that these leaves contribute heavily to the fact that my wild bettas almost never get sick.  

Many fellow betta-keepers use them as medication for classic diseases such as finrot, sometimes in combination with other medications. 

It has also believed that the leaves spread chemicals that have antifungal characteristics and can be used to lower the chance of fish eggs getting moldy. I have success using almond leaves myself with bettas as well as with corydoras eggs, who tend to mold fast.

Like stated before, the leaves are also used by a lot of local betta breeders who claim it strengthens the skin. and makes the skin heal faster.

Shelter and natural habitat

Apart from attributing to the direct health of your fish and adding useful chemicals to the water, catappa leaves mimic the natural substrate of betta fish. In the wild the substrate consists of various organic materials among which a big part of leaves.

When you add those leaves or extract to the water, bettas (especially wild bettas) will certainly notice this and feel more comfortable in a tank which is similar to their natural habitat. As you might know, when you add indian almond leaves to the water it colors brown. This color makes your bettas feel more safe and they prefer black water over clear tap water.

If you choose to add whole leaves to your aquarium it is great for males to build their nests in and later, when sunken as hiding places. If you have tank mates such as shrimp they will enjoy eating them as well.

Water parameters

The claims that catappa leaves lower the pH of your water are very anecdotal. Some say that the leaves lower their pH, others say it doesn’t. Catappa leaves are big business for most stores and they experience benefits the more positive effects catappa leaves have. Of course I’m not saying that people are lying when they say catappa leaves lower your pH, because they can, but just will not always do.

What we do know is that when the leaves are broken down, or when you add extract of it to the water it adds lots of tannins which could contain acids. Note that pH also depends on the KH (carbonate hardness), if your KH is high your pH will barely change or not change at all.

Also, it depends on how much you add. In comparison to the amount of water you probably have, one catappa leaf has miniscule acids in it. To have results you will add enough of the leaves and maybe more than you are planning on.

Finally, out of personal experience, I can say that the quality of your leaves is very important. Don’t waste your time searching for cheap leaves on sites like Aliexpress. Choosing high-quality leaves. The quality of your leaves is determined mostly by processing and how your leaves are collected, but also by the conditions of the tree.

So catappa leaves can certainly lower your pH, but you will need to pay attention to some things if you really want to lower your pH values by adding Indian almond leaves

How to use Indian almond leaves

Bought your leaves? Time to put them in your aquarium and make some fish happy. 

  • Put the leaves in your aquarium

The easiest and most used way to use your indian almond leaves is to put them whole in your aquarium. After the leaves are in your water for a couple of hours, they will start to release the desired tannins and your betta will start to enjoy the benefits. It is normal for the leaves to float and will only sink after 1-2 days. The floating leaves provide great support for males to build their nest under. When the leaves are sunken for a couple of days, most tannins will be released and you can take them out. Personally I prefer to leave them in the tank and let the plants, bacteria and other fish eat it. It provides nice extra shelter for your fish too. The amount of leaves you put in your tank is fully up to you. I recommend putting one medium sized leaf (6 inches) for every 8-10 gallons of water. The more leaves, the more tannins will be released and the darker your water will be.

  • Creating catappa leaf extract.

If you don’t like the look of the leaves in your tank or don’t want to take them out of your tank every time you can easily use catappa leaf extract. Catappa leaf extract is  basically just water with a very high concentration of catappa leaf concentration. When you add this to your water, it will instantly add all those good chemicals and tannins in the extract to your water. 

As stated above, it is very easy to create catappa leaf extract yourself. The only things you will need are a couple of indian almond leaves, a big bowl or jar where you can put boiling water in and water. 

Take your jar, boil the water and add one catappa leaf every 2 gallons. Some people remove the nerves, I personally have great results without doing it. The more leaves you will add the more concentrated your extract will be. Let the water cool down and then take the leaves out, who will have given all the tannins and chemicals to the water. If you want a very concentrated extract you can let it sit for some days.

A good test to check the quality of your leaves is to look if there is any cloudiness. If you can see dust in the water, your leaves are probably not the best quality.

Finding high-quality leaves can be a challenge though. Most leaves in the generic pet shop are bad. I buy mine at Chewy. Although many people buy there for their dogs or cats, they have interesting products about fish, too. You can buy high-quality leaves via this link.


There are several other materials on the market who can be a replacement for Indian almond leaves. Most leaves however will not have the same effects on your fish and will only be a partial replacement for your betta fish. The leaves will not have the same chemicals and tannins as catappa leaves

  • Alder cones
  • Alder cones are flowers from the black alder tree that have become woods. The cones can lower the pH and KH a little bit and add some tannins to the water. I personally like the appearance of the cones and they can be used as decoration too. What is very useful is that alder cones hardly break down in your aquarium, unlike most leaves who will break down after several days or weeks. 

    Buy alder cones at Chewy (my personal choice).

  • Banana leaves
  • Since banana leaves are pretty hard to get in the aquarium hobby they aren’t very well-known. However, banana leaves have some healing properties too and many people use them as a replacement for catappa leaves. They are comparable to catappa leaves in terms of use and shrimp love feating on them.

  • Oak leaves
  • Oak trees are very common throughout Europe and America. This makes the leaves great and cheap, and most people are able to collect them themselves. In large amounts they might lower the pH of your water. They are also great for culturing infusoria and as food for shrimp. What can be hard is that the leaves break down very fast and it can be hard to take them out of your tank. Only pick up the naturally fallen leaves in autumn, those have the most useful chemicals in them.

  • Other fruit tree leaves
  • Most dried leaves from fruit leaves are great for your aquarium too. Please do your research before using any leaves. and only use leaves naturally fallen off the tree. Examples are leaves from walnut trees, guava leaves and apple trees. Make sure to take leaves from areas you know sure aren’t polluted in any way.

    Where to buy Indian almond leaves

    Buying high quality leaves is important to assure your fish will benefit from the leaves. Things who can determine the quality of your leaves are how they are harvested, dried and processed. I recommend buying leaves from reliable shops who you can trust and where leaves are naturally dried.

    To be honest, I always bought my leaves from the local pet shop. Unfortunately, it closed down due to covid. As of this moment, I get all of my leaves at Chewy (since I buy other pet stuff there, too). You can buy the leaves I buy via this link:

    Buy Indian Almond leaves at Chewy (my personal choice) →

    Final thoughts

    Indian almond leaves are in my opinion a must for every betta or fish keeper in general. The unique combination of tannins and other chemicals mimic exactly what our wild bettas prefer in nature. The tannins work against illness, prevent them and strengthen your fish overall. It provides great cover and can lower your pH. The only disadvantage some people find is that the leaves color the water, so if you don’t like a more natural look the leaves might not be for you. Be careful however where you buy them and pick a store you trust, because not all quality is the same.