Catappa Leaves for Aquariums: The Ultimate Guide


Catappa leaves, also known as Indian almond leaves, have long been used by Betta breeders to encourage spawning and protect eggs and fish from fungal infection. Not only for Betta breeding, these useful leaves are finding applications with other species. Hobbyists setting up blackwater aquariums use Catappa leaves to give their fish natural and healthy water conditions that can mimic their habitats in the wild.

Catappa leaves come from the Catappa Tree, Terminalia Catappa. A large tropical tree native to Asia, Australia, the Pacific and Madagascar, T. Catappa can reach heights of 115 feet. Natural medicine treatments in some Asian countries use the leaves for ailments ranging from liver disease to dysentery and diarrhea.

In an aquarium, the dried leaves are added directly to the tank to adjust the water’s chemistry. While benefiting some species of fish this can also color the water light yellow or brown. When trying to mimic aesthetics of natural environments this can be desirable, but can come as a surprise to those not familiar with Catappa leaves.

Let’s look at some details about Catappa leaves to see how, and if, you’ll want to use them in your aquarium!

What are Catappa Leaves used for?

Catappa leaves are used to increase acidity in aquarium water. They also release chemicals known to be beneficial to certain types of fish. This includes compounds that have antibacterial and antifungal properties.

Catappa leaves can help reproduce the blackwater environments that certain fish species prefer–in chemical composition and color. Introducing these leaves will tint tank water brown, important for mimicking the look of a blackwater habitat.

Often used by Betta breeders, Catappa treated tank water can encourage these fish to spawn. The leaves release chemicals claimed to help eggs resist fungal infections.

Blackwater aquarium enthusiasts will use Catappa treated water to give their tanks a more natural appearance and chemical composition. Fish native to blackwater are more comfortable in water that reproduces their natural habitat.

Catappa Leaves
Catappa Leaves

Benefits of Using Catappa Leaves for Aquariums

Using Catappa leaves in aquariums can raise acidity and soften the water. Certain fish species benefit from chemical compounds released by the leaves that can reduce bacterial and fungal infections.

Fish species from blackwater environments may not thrive in the clear water common in most hobbyist’s aquariums, even if the pH and water hardness are correct. The chemicals released by Catappa tint the water and introduce chemicals similar to those found in nature. Fish species which have bred in captivity for years may be accustomed to water without these added compounds. Other species newer to the aquarium hobby may prefer more natural water composition, including tannins and other chemicals released by Catappa leaves.

Are Catappa Leaves good for all fish?

Catappa leaves are not suitable for all fish. Particularly those species that prefer alkaline environments. Before treating your aquarium water with Catappa leaves make sure you understand the benefits and drawbacks.

Are Catappa Leaves Beneficial for Betta?

Catappa leaves are commonly used when Bettas get sick, usually in combination with other medication. Regular application can help to mimic a natural habitat.

In nature, Bettas live in the slow streams and marshes of Thailand and Cambodia. These environments will often contain large amounts of decaying plant matter and tannins. Adding Catappa leaves can bring some of that natural environment to your Betta tank. A downside to this tinted water. The impressive coloration of Bettas can be obscured by the brown tint of Catappa treated water. Many hobbyists prefer their Bettas live in clear water for this reason.

Another benefit of adding Catappa leaves to Betta tanks is to encourage breeding. The male Betta will build his bubble nest under Catappa leaves while they are floating. The chemicals released may encourage spawning in other ways and can reduce fungal infections in eggs.

Are Catappa Leaves Beneficial for Shrimp?

Catappa leaves can help freshwater shrimp by adding beneficial chemicals to your water. As the leaves decay they become coated with a biofilm that shrimp eat.

With fish, Catappa leaves are prized mainly for the helpful compounds they add to your water, for shrimp they can also provide a food source. Depending on the population of a community tank, shrimp may need no additional feeding as they will scavenge uneaten food and algae. Decomposing Catappa leaves are a source of biofilm and a magnet for algae. Shrimp eat these byproducts as well as benefiting from the chemicals released by the leaves.

Catappa leaves can be floated on the surface of your tank. As the leaves become waterlogged and decay your shrimp will use them for shelter and food!

Are Catappa Leaves Beneficial for Discus?

Discus originate in blackwater environments. Generations of captive breeding have made them more tolerant of clear aquarium environments. Catappa leaves may be unnecessary for these fish.

When creating a blackwater aquarium that will include Discus, Catappa leaves can safely be used to tint the water and are appreciated by certain tank mates such as freshwater shrimp.

Are Catappa Leaves Beneficial for Guppies?

As guppies prefer neutral water with a pH near 7.0, Catappa leaves may raise ascidity beyond what they can tolerate. Catappa leaves should be used with caution in guppy tanks, if used at all.

Are Catappa Leaves Beneficial for Axolotl?

Catappa leaves can help Axolotls resist fungal infections and disease but should be used with caution as they can raise acidity levels in your tank. With Axolotls, you should probably not use Catappa leaves regularly in their aquarium. An occasional application can be helpful. Make sure to check your water chemistry regularly and prepare to use water changes to dilute the treated water as needed.

How to Use Catappa Leaves in an Aquarium?

Catappa leaves are used by floating the needed number of dry leaves on the surface tank water. They will become waterlogged and sink in about 4 days. The leaves can then be removed after a few weeks. Some people will simply leave Catappa leaves in their tanks until they decay. This can results in piles of rotten Catappa leaves laying in the tank. This can help give aquariums a natural aesthetic. If this isn’t desired be sure to remove the leaves before they begin to fall apart.

Some hobbyists who don’t want floating Catappa leaves will pre-soak or boil the leaves before placing in their aquariums. But pre-soaking or boiling can take many of the beneficial compounds out of the leaves before they ever get to tank water. One situation where boiling Catappa leaves is useful? When you want the effects without ever putting the leaves in your tank. Do this by boiling the leaves, straining out the solids, then cooling and storing the resulting “tea” in a refrigerator where it can keep for a couple of months. One thing to watch for here is dosing. It’s hard to measure the strength of your Catappa leaf “tea.” Overdosing your tank is a possibility so exercise caution when using this method.

How many Catappa Leaves should be used per gallon?

When adding Catappa leaves directly to your aquarium, start with 1 leaf per 15 gallons. Dried Catappa leaves are a natural product so it can be difficult to gauge their strength. When working with a new batch of leaves, exercise caution until you see how much of an effect they will have. Always check your water chemistry during treatment. Especially for the first week or two. Adding anything to your tank can cause unexpected water changes.

How much do Catappa Leaves lower pH?

Catappa leaves are known to lower aquarium water pH but the amount is debatable. Some hobbyists report pH changes that are barely noticeable. Different results can come from different tank setups and different batches of Catappa leaves. Monitor your water quality and pH when working with these leaves for best results. If pH swings too wildly, remove the leaves and do a partial water change reduce the concentration.

How long do Catappa Leaves last in an aquarium?

Catappa leaves produce most of their chemical effects in two weeks. They will stay whole for 1 to 2 months before disintegrating. If you don’t want piles of Catappa leaves littering the bottom on your tank remove them before they begin to break down.

How often should the Catappa Leaves be changed in an aquarium?

Catappa leaves are can be removed from an aquarium after 3 weeks. This gives them time to release helpful compounds but not begin breaking up. In some cases disintegration is desired. Hobbyists trying to reproduce natural blackwater environments may prefer never removing the leaves. Instead letting them break up and become food for tank bacteria and shrimp.

Changing leaves is only required if you want your fish in constant contact with Catappa “tea.” This might not be desirable. Some hobbyists who use Catappa leaves will only leave them in the tank for a few weeks every couple of months, or as needed for fish health.

Fish Laboratory

With decades of collective fishkeeping experience, we are happy to share the fish care tips that we've picked up along the way. Our goal at Fish Laboratory is to keep publishing accurate content to help fishkeepers keep their fish and aquarium healthy.

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