Are Indian Almond Leaves Good For Aquarium Fish?

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Are Indian Almond Leaves Good for Aquarium Fish?

Have you ever seen a stack of large, dried leaves at the fish store and wondered what they are for? Terminalia catappa is the source of Indian almond leaves (IAL), or catappa leaf. This tree, originally from Asia and Oceania, now grows in tropical and semi-tropical areas all over the globe. Its fruit seeds are similar to almonds. The leaves of Terminalia catappa are often used in herbal teas as well as traditional medicines.

Fruit and leaves of the Indian almond tree

When you drop a dried catappa leaf into your aquarium water, the leaf begins to slowly decompose and produce tannins, which are plant-based compounds that gradually lower the pH and stain the water with a yellow-brown tint. Although many people don’t like the natural tannins produced by leaves or driftwood, chemical filtration can be used to remove the brown tint.

What is the purpose of Catappa Leaves?

If you are a sensitive species (like crystal shrimps and certain South American fish), that may be a preference.

Low pH water and low pH water

Indian almond leaves slowly lower pH levels by releasing tannic, humic, and fulvic acid organic compounds. While they take longer than pH buffer chemicals to work, their gradual effect is often considered safer because they are less likely be to cause deadly pH swings. They have a detrimental effect on water chemistry so they are not recommended for high pH fish like African Cichlids or other livebearers.

While some soft water fish don’t require low pH for their normal living conditions, you may be more successful with breeding and raising their fry if you make the water more acidic. This is why breeders frequently use catappa leaves together with Apistogramma piscichilds or betta fish (both wild type and Betta splendens). The leaves are able to float for a few days so gouramis or betta fish can create bubble nests beneath them to provide additional support.

Betta Fish in an Aquarium with Tan-Tinted Water

It is interesting to note that Indian almond leaves have slight antibacterial or antifungal properties. The tannins in plants help protect them from pathogens like bacteria and fungus. Scientists continue to investigate their effectiveness for human medicine. Therefore, many aquarists like to use catappa leaves to heal mild ailments and aid their fish’s immune systems. Tannings can be helpful for betta fish who bite their tails. For fungal growth prevention, experts suggest adding alder cones or tannin-rich leaves to hatch fish eggs.

Microorganisms consume the Indian almond leaves as they soak in water. They quickly reproduce and form a layer of infusoria. This microfauna can be a great food source for tiny shrimp and fry. It is often the only food that is small enough to be eaten by them in their first stages of life. If you plan on going out of town and have no one to feed your shrimp colony, try soaking several leaves in a bucket of water for three weeks until they become very slimy with biofilm. Then drop them in your aquarium as a long-lasting vacation food while you’re gone.

Blackwater biotope aquarium that imitates a Brazilian forest stream

Finally, if you want to create a South American biotype or blackwater aquarium that simulates your fish’s natural environment, use lots of catappa leaves and other botanicals to cover the ground. This makes brightly colored fish, such as neon tetras or cardinal Tetras, stand out. It also helps skittish fish feel more comfortable since they are more hidden from view by the tannins in the tank. If you add enough Indian almond leaves, the leaf litter can serve as hiding spots for fry or shy bottom dwellers like pygmy corydoras.

How to Use Indian Almond Leaves

You can wash the leaves in water if they are extremely dirty or dusty. However, the catappa leaves that Aquarium Co-Op sells are so clean, we simply drop them into the fish tank. They usually float for the first 3-7 days, so if it bothers you, weigh them down with a rock or decoration. Also, you can break the leaf in half to just use part of it or crumble it into smaller pieces to speed up the decomposition process.

Dried catappa leaves, ready for use in aquariums

How many catappa leaf should I use for 5-20 gallons? For blackwater tanks, you will need to use more leaves and other soft woods (like Malaysian driftwood or cholla wood) until the desired color is achieved.

Do I boil Indian almond leaves for their health benefits? Not because boiling them releases the tannins. However, if you don’t like the way the leaves look, some people like to make a catappa leaf extract by boiling one leaf for every 0.5 gallon (2 liters) of water. It is best to avoid using a pot that you aren’t concerned about as it could stain. Once the liquid has cooled, pour a little into the tank until you reach the color you want. To dilute too much extract, you can simply add more water to the tank.

When should I replace the catappa leaves? Most leaves last about one to two months until they break down completely. Add another leaf to the plant to allow it to break down and release tannins.

Caridina cantonensis shrimp chomping on the remains a catappa leaves

If you are thinking about keeping shrimp or breeding softwater fish, or creating a blackwater biotope for your aquarium, grab some catappa leaves. Aquarium Co-Op leaves are precleaned and ready to use right out of the package.