Catappa – Indian Almond Leaves: Benefits in the Aquarium

Indian almond leaves don’t sound like something you’d use for an aquarium, but they can be surprisingly useful.

This guide will teach you about these cool leaves and how they can help take your tank’s health to the next level.


Indian almond leaves are one of the best kept secrets in the trade! You can often see these dried leaves staining the waters of freshwater aquariums around the world. They are a favorite of experienced aquarists looking for a natural alternative to expensive water conditioners or medications.

But what exactly are they?

These brown leaves come from the Terminalia catappa tree. In less scientific terms, it is usually simply called the Indian almond tree. It is a large tropical tree that is part of the leadwood family.

The tree grows throughout southwestern Asia, Africa, and even Australia. It produces nuts, which often contribute to local cuisine and trade. However, it is the leaves that are most sought after.

Throughout history, almond leaves from India have been a mainstay of traditional medicine. Even today, humans use it to treat common ailments as a home remedy. Many believe that the medicinal properties translate to fish as well!

In many cases, the Indian almond tree lines the banks of rivers and grows alongside bodies of water teeming with fish. Leaves naturally fall into the water below and impact water quality. These trees produce a lot of leaves, so the effects are not subtle.

Author’s Note: While many would think that leaf litter would negatively affect fish, the reality is the opposite! Indian almond leaves play an important role in shaping many underwater ecosystems.

These days, Indian almond leaves are available at most pet stores. The collectors collect the leaves once they fall to the ground. They go through a natural drying process before going to stores, making them easy to use for fish keepers of any level.


Many experienced aquarists swear by Indian almond leaves! They look like simple garden debris, but the effect they have on the water in your tank is amazing.

Here are some ways you can use them to benefit your underwater habitat.


Some refer to Indian almond leaves as a natural water conditioner. What comes out of the tap is not the most conducive to fishing. It is treated in a plant and is nothing like the natural rivers and streams that your fish come from!

While you can use expensive conditioners, Indian almond leaves are a much better alternative.

Indian almond leaves release tannic acids and other beneficial substances, which many simply refer to as “tannins”.When submerged in water, the leaves break down and release those tannins into the water. It even stains the water, creating a yellow or brown look!

The color change is similar to what you would see when straining a tea bag in hot water. Brown tones can be a bit startling at first. But do not worry! Change is great for your fish!

Author’s Note: Do some research and see what kind of environment your fish come from. The water will most likely be dark brown or even black. That coloration comes from the tannins.

It’s not just an aesthetic change that happens. Tannins also significantly improve water quality. Tannic acids have medicinal properties for both humans and fish.

Tannins improve pH levels and can also reduce overall harshness. But more importantly, it replicates the natural environment of your fish. That alone can make your aquarium much healthier.

Stress can be a serious problem in fish tanks. Having a familiar environment stained with tannins can go a long way in helping your fish stay happy and healthy. Combine that with all the medicinal properties and you have top notch water conditions that will help your fish thrive.

They are a common sight in betta fish tanks and freshwater shrimp tanks. But, most tropical freshwater fish will benefit from those tannins.


If you have fish that prefer lower pH levels, Indian almond leaves are a must. Not all fish will enjoy slightly acidic water, but the vast majority of tropical species do better at a lower pH.

Indian almond leaves naturally lower the pH balance in an aquarium. Not only that, but it also helps reduce carbonate hardness, which contributes to the overall pH.

Lower pH readings are ideal for many freshwater fish. It is closer to what you experience in nature. Also, acidic water is better at controlling bioburden.

Ammonia levels tend to rise faster in neutral or high pH water. That’s because ammonia takes longer to convert. At a lower pH level, ammonia can be quickly converted to the less fatal ammonium. As a result, your aquarium will stay healthier and cleaner for your fish!

The tannins that come from the leaves of the Indian almond act gradually.It takes time for the leaves to work their magic.

But this is a good thing!

Many commercial products drop the pH suddenly. While it’s good on paper, the change can be a bit drastic for your fish. Also, the effects are temporary at best.

Author’s Note: Water conditioners use mild acids or bases to combat rising pH levels. But those additives wear off after a while, bringing water conditions back to square one. With Indian almond leaves, the change is gradual and lasting.


Believe it or not, Indian almond leaves are believed to address a wide range of health issues with your fish.

Remember how we said that these leaves are part of traditional medicine? Well, humans have used them for centuries to tackle bacterial and fungal problems.

The tans produced by the leaves are said to have natural antibacterial and antifungal properties. It all comes down to why tannins exist in the first place!

In a healthy tree, tannins usually remain within the bark and leaves. The tree uses the tannins to extract enzymes from bacteria and fungi. It is the tree’s natural defense mechanism against infection!

When tannins leach from the leaves into the water, this natural infection-fighting property benefits the fish.

The leaves can help strengthen the immune system of fish and invertebrates.All the creatures in your tank have the power to fight pathogens in the water. But if their immune system is weakened, they can start to get low-grade infections.

Infections typically manifest as fin rot, various skin problems, and viruses. Those infections can quickly spread throughout the aquarium and affect other fish along the way.

Indian almond leaf tannins can address those issues and create a much healthier environment.

Many aquarists prefer to use the leaves instead of traditional medicines. Some will use the leaves in quarantine tanks to speed up the healing process. Others will take advantage of its healing properties to prevent infections from jumping.

Author’s note: They are particularly useful for fish that have long, flowing fins, such as bettas. There is anecdotal evidence to suggest that it helps fight infections like fin rot.


The dark coloration that comes with the tannins in the Indian almond leaf can go a long way in making your fish feel more secure. That slight tint helps to scatter light differently and creates a more comfortable environment for more timid fish. On top of that, the leaves themselves offer plenty of places to hide!

Smaller fish and shrimp will appreciate this extra protection the most.They can quickly hide under leaves whenever larger fish come near. Fingerlings can benefit too!

Either way, it doesn’t hurt to have a few extra hiding places for smaller species. Indian almond leaves do not take up much space. But they create those extra hiding places that can make all the difference.


Speaking of fish fry, many aquarists use Indian almond leaves to induce spawning. These leaves offer two distinct benefits: protection and better water quality.

As mentioned above, Indian almond leaves make a great hiding place. Some species of fish need this to start spawning. This is especially true in a larger community tank.

Almost all fish in the aquarium present a clear danger to the eggs and fry! Hungry fish are quick to gobble up any high-protein snack, and that includes baby fish.

Many species will also delay breeding because the tank lacks any form of protection.Indian almond leaves may offer the protection they seek. Some species, such as betta fish, will actively use leaves to create nests. Bettas like to create their bubble nests under floating leaves.

Meanwhile, other species may lay their eggs on the underside of submerged leaves. Whichever the case, the leaves keep the eggs hidden from hungry eyes! Fish fry can also use the leaves to stay out of harm’s way once they are free-swimming.

Indian almond leaves can also improve water conditions to promote spawning. Some species are notoriously difficult to breed because they require very specific water parameters! They may need lower pH levels, slightly darker waters, or good hardness ratings.

Those species will love having Indian Almond leaves in the environment. The leaves will lower both the pH level and the carbonate hardness levels. In addition, the staining limits the penetration of light in the lower part of the water column. All these factors encourage spawning in more demanding species.


If you have shrimp in your tank, Indian Almond Leaves can help them reach their full potential! Most shrimp species are natural herbivores.

They look for plant detritus, algae and small microorganisms to eat. While you can provide some food here and there, most prefer to forage on their own.

Indian almond leaves are an excellent food source. They are perfect for dwarf shrimp that cannot eat larger foods.

As the leaves break, the shrimp will feed on the remains. They continue to chop the leaves until there is nothing left. This helps with the natural degradation process while giving your shrimp a nutrient-dense food source.

Author’s Note: It’s not just the leaves that they eat. The decomposition process attracts microorganisms, such as infusoria. Those microorganisms are practically invisible to the naked eye, but they make excellent food for shrimp!

Many shrimp farmers report better overall health when there are Indian almond leaves in the tank. Not only that, but experienced aquarists say that it encourages higher reproduction and a better survival rate for shrimp.


The beauty of Indian almond leaves is that they are versatile and easy to use. There are no precise measurements to worry about and no complicated steps to follow. In the wild, these leaves work their magic without any human intervention!

In your home aquarium, you can choose to use them in a number of different ways. Here are some of the most common methods.


The typical way that Indian almond leaves are used by aquarists is simply by dropping them into the aquarium! Submerged leaves will slowly break down over time, releasing their tannins to infuse the water and improve conditions.

Before adding the leaves, check your filtration system. Remove any activated carbon items you may have. Charcoal removes stains. More on that later!

Author’s Note: It’s also a good idea to rinse the leaves first. You don’t want any leftover dust or debris getting into the tank.

Generally, a medium size sheet is adequate for a small 10 gallon tank. If you have something larger, add as many sheets as you need while staying within that ratio.

Let the leaves sink to the bottom and let them be. You can place them strategically to create hiding spots or allow them to fall naturally. The choice is yours!

Some aquarists will soak the leaves for a few weeks before removing and replacing them. That choice is up to you, but if you have shrimp and other tiny creatures that feed on the leaves, it’s best to let them decompose completely.


If you want to block out some light, letting the leaves float is a good option. Leaves will create a darker environment. Also, some species of fish can take advantage of the surface shelter to build bubble nests.

Generally, floating leaves will not last as long. As the organic material softens and breaks down, it will sink to the bottom of the tank. However, it can provide temporary shelter for a week or so.


Another unique option is to create a substrate from torn leaves. For this technique, you need to wash the leaves and break them into small pieces.

You can use the leaves alone to create a thin layer of organic substrate. Or you can adopt the same method to cover existing sand or gravel. In nature, decomposed leaf litter is the norm!

Using this technique can really help you take that natural setup to the next level.

Author’s Note: Leaf substrates tend to decompose slightly faster than whole leaves. However, manageable pieces will create a feast for hungry shrimp and invertebrates.


Want to take advantage of Indian almond leaves without the added waste? If so, you can create a tea that is poured into your aquarium! It acts as a powerful extract of tannins.

Almond leaf teas from India are very common. You may even see them sold in stores!

Making the tea is a piece of cake. Get a large glass jar or heat resistant container. Then place a couple of medium-large leaves inside. If you want to create a super potent tea, you can fill the jar halfway with leaves.

Author’s Note: However, this is not required. A couple of leaves will create a strong extract either way.

Pour about two liters of water over the leaves and let the mixture sit overnight.

In the morning, remove leaves and litter. The water should be dark yellow or brown, depending on how many leaves you used.

You can open the lid and store the extract in your refrigerator for several months. When ready to use, add approximately two tablespoons per gallon of water in the aquarium. That ratio should dilute it enough while still benefiting the tank.


Whether you create an extracted tea or let the leaves steep in your tank naturally, you’ll notice the water change color. Depending on how many Indian almond leaves you use, it can vary from a subtle yellow tint to a deep brown.

Don’t let the color fool you. Your tank is not dirty!

The coloration comes from tannic acids. When released from the leaves, they infuse the water with those characteristic brown tones.

The color is not dangerous for your fish. It is also not a sign of a dangerous or unhealthy tank. The effect is the same as steeping tea leaves for drinking. A slight coloration just means your fish are taking advantage of the antifungal and antibacterial tannins!

In nature, those tannins can make water look downright cloudy. Some bodies of water take on a deep black color because of all the staining.

Author’s Note: If you’re not too into the look, the tannins are pretty easy to lighten. All you need is activated carbon. The charcoal will absorb the tannins, which can help lighten the brown color or remove it altogether.

Keep in mind that activated carbon filters can only do so much before they need to be replaced. If you want to control the coloration of your water, you will need to replace old filters with newer ones periodically.


Using too many Indian almond leaves is more difficult than you think.

Remember: Many fish come from natural blackwater that completely blocks out light! Fish enjoy the tannins and generally have no problem with deep color staining.

The only way to use «too much» would be if you used a ridiculous amount of leaves and left very little room for your fish.

All that said, keep an eye on the pH levels.You don’t want things to go below your fish’s comfort levels.

In case you have gone a little overboard with the Indian almond leaves, there are some easy solutions. The first is to take advantage of activated carbon filters. As we said before, the carbon will absorb the tannins until it clears the water.

You can also perform partial water changes. Change 25 percent of the water every few weeks to lighten the tannin load.

Author’s note: It is rare to use too much Indian almond leaves. But to be safe, limit yourself to one medium sized sheet per 10 gallons.


Indian Almond Leaves are an excellent choice for aquarists looking to naturally improve the quality of their tank. As long as your fish are compatible with the conditions these sheets help facilitate, we think you should consider giving them a try.

Let us know if you have any questions that we don’t cover in this guide. We are more than happy to help you!

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