Indian Almond Leaves (also known as Catappa or Ketapang leaves) have been used for both therapeutic and medicinal purposes in the aquarium hobby for many years. They are said to simulate the natural environment for fish such as Bettas, Killies, Discus, Arowana, Tetras, Appistogramma, Dwarf Cichlids, Rasbora, Corydoras and other Catfish, and Shrimp. They also boast proven healing and therapeutic benefits.

Indian Almond Leaves for Aquariums

Probably the most common myth about Indian Almond Leaves in the aquarium, is that their benefits simply come from their tannins. This simplistic view has lead to the misconception that any leaf can offer tannins with the same benefits. This couldn’t be further from the truth.

Humic acids (including tannins) do offer some seemingly universal benefits. Tannins offer antibacterial properties and are a component in many herbs. In this respect, any safe source of tannic acids may benefit the aquatic environment.

However, the leaves from some tree species (or any herb) offer further therapeutic or medicinal properties based on their varying active components. The type, amount, and combination of these components varies widely from species to species. For example, a 2009 study on Ficus benjamina discovered that a newly identified triterpenic acid exhibited significant antimicrobial activity against Salmonella typhimurium, Candida albicans, Staphylococcus aureus, and Escherichia coli, as well as low activity against Aspergillus niger and Aspergillus brassicola. Other species offer triterpenic acids, but the Ficus offers a unique triterpenic acid that you would not benefit from if you used another species.

It’s highly unlikely that all of the active components in each species have been identified, but certainly many have. One study proved that triterpenic acids 1 and 2 are two of the acids responsible for the anti-inflammatory activity of Indian Almond Leaves, for example. Analysis of Indian Almond Leaves thus far has revealed flavanoids, isovitexin, vitexin, isoorientin, rutin and triterpenoiods. Further identified are volatile oils, quercetin, corilagin, kamferolphenols, saponin, saponin glycosides, cardiac glycoside, balsam, and squalene. T. catappa leaf tannins include punicalagin, punicalin, geranin, granatin B, tergallagin, tercatain, terflavin A and B, chebulagic acid, and corilagin.

Scientific and Anecdotal Evidence

T. catappa Leaves for Aquariums
Indian Almond Leaves are sold dry, either whole or in tea bags.

The medicinal properties of T. catappa have been proven repeatedly in scientific studies (see references below):

  • Anti-inflammatory
  • Antiparasite properties, including the eradication of Trichodina, Gyrodactylus sp. and Dactylogyrus sp.
  • Antibacterial properties have been proven against many strains, both negative and positive, and T. catappa leaf extracts continue to be explored as an alternative to antibiotics for the food fish industry.
  • Scientists have reported antifungal activity against Pythium ultimum, Rhizoctonia solani, Sclerotium rolfsii, and Aspergillus fumigatus. Indian Almond Leaf extract has also been used successfully as an antifungal for Tilapia eggs.
  • Immune system support has been verified in humans, to a point where it has helped HIV patients.

Hobbyists report:

  • Rapid healing
  • Increased spawning activity
  • Improved offspring male/female ratios
  • Vibrant colour
  • Improved fin health & size
  • Exceptional overall health & vitality

As a treatment or for therapeutic benefits, the results are almost universally agreed upon by aquarists. Indian Almond Leaves won’t cure everything, nothing will, but they have been both scientifically and hobbyist proven as an effective treatment for many ailments and for immune system support.


How much Indian Almond Leaves or extract is required will depend upon your water chemistry. Hard water with a high KH will require more than soft water with a lower KH. If you have blackwater fish or are using Indian Almond Leaves medicinally, you may wish to use more. If you are looking for therapeutic benefits, you’ll want to use less.

Note of Caution

Studies have shown varying tolerance levels among fish species. Guppies were proven to suffer toxic effects and gill adhesion at lower levels than Bettas tolerated, for example. This suggests that you should proceed with caution, gradually increasing the amount you add to your aquarium. We also suggest that you monitor pH levels to ensure that they don’t lower too quickly. If your aquatic pets appear to be stressed, remove the leaves, do a large water change, and/or add activated carbon to your filter.

Goun E, Cunningham G, Chu D, Nguyen C, Miles D. Antibacterial and antifungal activity of Indonesian ethnomedical plants. Fitoterapia. 2003.
Chitmanat C, Tongdonmuan K, Khanom P, Pachontis P, Nunsong W. Antiparasitic, antibacterial, and antifungal activities derived from a Terminalia catappa solution against some tilapia (Oreochromis niliticus) pathogen. 2005.
Chansue N, Tangtrongpiros J. Effect of Dried Indian almond Leaf (Terminalia catappa) on Monogenean Parasite of Gold Fish (Carassius auratus). 2005.
Masuda T, Yonemori Y, Oyama Y, Takeda T, Tanaka T. Evaluation of the antioxidant activity of environmental plants: activity of the leaf extracts from seashore plants. J Agric Food Chem. 1999.
Scalbert A. Antimicrobial properties of tannins – Phytochem. 1991.
Baek Nam-In; Kennelly E.J.; Kardono L.B.S.; Tsauri S.; Padmawinata K.; Soejarto D.D.; Kinghorn A.D., Flavonoids and a proanthrocyanidin from rhizomes of Selliguea feei. Phytochemistry, 1994.
Tan GT, Pezzulo JM, Kinghom AD, Hughes SH. Evaluation of natural products as inhibitors of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase. J Nat Products. 1991.
Treves-Brown KM. Externally applied antimicrobial agents. Applied fish Pharmacology. Netherlands. 2000.
Fan YM, Xu LZ, Gao J, Wang Y, Tang XH, Zhao XN, et al. Phytochemical and antiinflammatory studies on Terminalia catappa. Fitoterapia. 2004.
Chansue Nantarika, Assawawongkasem Nongnut. The in vitro Antibacterial Activity and Ornamental Fish Toxicity of the Water Extract of Indian Almond Leaves (Terminalia catappa Linn.). KKU Vet J. 2008.
Using Indian almond leaves in aquariums Accessed October, 2010.
Chung KT, Lu Z, Chou MW. Mechanism of inhibition of tannic acid and related compounds on the growth of intestinal bacteria. Food and Chemical Toxicology. 1998.
Chansue N, Mataderm T, Suilasuta A. Preliminary study of Effects of Dried Indian Almond Terminalia catappa leaf on ultrastuctural morphology of scale in Siamese Fighting Fish (Betta splendens). 2004.
Chansue N, Tangtrongpiros J. Efficacies of dry Indian almond leaf (Terminalia catappa) and Andrographis paniculata (Burm. F) Wall. Ex Nees Extract on tail regeneration and Hematocrit of Fancy Carp. J Thai Vet Med Assoc. 2006.
Chitmanat C, Tongdonmuan K, Nunsong W. The use of crude extract from traditional medicinal plants to eliminate Tricodina sp. In tilapia (Oreochromis niliticus) fingerlings. Songklanakarin J. Sci. Technol. 2005.
Watchariya P, Surapon W. Nontawit A. 2004. Efficiency of some Herbals for eliminate Zoothamnium sp. and toxicity on Penaeus monodon Fabricius. 2004.
Chansue N. Effects of Dried Indian Almond Terminalia catappa leaf on Hematology and Blood chemistry of Siamese Fighting Fish (Betta splendens). 2003.
Parveen Mehtab. A novel antimicrobial triterpenic acid from the leaves of Ficus benjamina (var. comosa). King Saud University. 2009.

✔ You may also be interested in reading:
Increase Or Decrease Freshwater Aquarium PH Naturally
Natural Fish Foods and Supplements for Fancy Fins
Natural Prevention and Treatment of Aquarium Fish Parasites


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