Articles Water quality

Indian Almond Leaves | How and when to use them!

June 1, 2014
indian almond leaf

If you’re an aquarist, you’ve probably heard of Indian almond leaves (also known as Catappa leaves). These leaves of the Terminalia catappa tree are especially popular in the betta and shrimp hobby as a natural medicine and water conditioner. They are said to help combat fungus and bacterial problems like finrot, and prevent stress by mimicking the natural habitat. But how, when and why should you use them?

What are Indian almond leaves?

As mentioned before, Indian almond leaves are the leaves of the Terminalia catappa tree, which grows in large parts of Asia. The leaves are usually harvested by simply picking them off the ground. After drying them, they are ready for use in the aquarium. You can import Indian almond leaves directly, but nowadays they are also available in some pet-/aquarium stores and online!

What do Indian almond leaves do?

When placed in an aquarium, Indian almond leaves slowly start to decompose. While this happens they turn the water a yellow or brown color by releasing tannins. These tannins lower the pH and are said to have antifungal and antibacterial properties, which comes in very handy when you have a fish suffering from finrot or when you’re raising vulnerable fry. The dark color of the water is considered unsightly by some aquarists, but it actually mimics the natural habitat of many fish species! This definitely makes it something to consider embracing.

When should I use Indian almond leaves?

Indian almond leaves are especially popular in the betta and shrimp hobby but can be used in many situations.

  • Adding a few leaves to a quarantine tank with a sick fish can help speed up the healing process; I’ve spoken to betta breeders who have actually stopped using regular fish medication altogether and treat sick fish with nothing but Indian almond leaves and clean water.
  • When you’re dealing with fish/invertebrates that prefer soft, acidic water, Indian almond leaves can also be great for stimulating breeding. The tannins released by the leaves help create water conditions that are similar to those in the natural habitat of the fish, which means ideal breeding conditions. If you’re trying to get your bettas or Crystal Red shrimp to breed, adding a few Indian almond leaves to the breeding tank can speed up the process!
  • Lastly, there are also situations where Indian almond leaves can be added to the aquarium purely because of the way they stain the water. If you’re interested in setting up an Asian blackwater biotope, which imitates blackwater rivers and streams, Indian almond leaves are a must have. They appear in these regions naturally so they are biotope correct. You can also add the leaves to other aquarium setups with fish that prefer soft, acidic water if you like the look of it.
River through the trees

A blackwater river in Thailand. River through the trees

How do I use Indian almond leaves?

There are a a few different ways to use Indian almond leaves; the easiest is to just place them in the aquarium and wait for them to do their job/ The more you add, the darker the water gets. You can tear the leaves up if you want the tannins to release more quickly. Once the they start decomposing you can take them out or replace them, but it’s also fine to wait for them to be completely decomposed. Shrimp will actually appreciate it if you don’t remove the leaves, as they feed on the decomposing remains.

If you’re not a big fan of leaf litter in your tanks, another option is to soak the leaves separately and adding the stained water while doing a water change. You can also make your own blackwater extract, which is a concentrated version of stained water. This is done by taking a very large amount of Indian almond leaves, boiling them in a pot of water and letting them soak for multiple days afterwards. You only have to add a small amount of the extract to your aquarium to get that blackwater look. (And by the way, if you’re not the kind of person who stands around boiling leaves, you can also just buy your Indian almond leaf extract! We don’t judge.)

I have used Indian almond leaves while treating a sick betta before and I definitely recommend giving it a try. Many breeders swear by it and the leaves are not expensive at all. I personally also love the look of stained water; very natural and it can be a part of fantastic looking aquascapes!

If you have any more questions about Indian almond leaves and their use, leave a comment below. Happy fishkeeping!

Cover photo: Hojas de Terminalia catappa by Mapilonga

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  • Reply Buddika September 15, 2016 at 7:09 pm

    Hi, I have a outdoor water pond with fish. I need to keep my fish in healthy and safety . How to use almond leaves for outdoor water.

    • Reply Mari September 17, 2016 at 12:41 pm

      Just as you would indoors! The instructions in the article work for ponds as well.

  • Reply Arun Raja June 2, 2016 at 7:24 pm

    I’m from South India, here almond leaves can be found in abundance. I have a few 1 gallon aquarium for bettas and this leaf will take a few days to decompose, and only after that it will look brownish. Would you recommend me to clean the aquarium (water change) after it turns brownish? I hope the process will be initiated only after a couple of days. Thankyou..

    • Reply Mari June 3, 2016 at 10:47 am

      1 gallon tanks are too small to keep bettas in (unless you’re an experienced breeder), so please upgrade your fish! The brown stained water is not a problem at all, though obviously you should still do water changes often to keep water quality high.

  • Reply Kimberly May 17, 2016 at 10:41 pm

    Is it harmful to put too much IAL in a tank? I’m in the process of moving so I have 1.2 gallon QT tank until I can get the 2.5 gallon set up again. I bought IAL from amazon by tantora size medium (5-7 inches ). Would 1 leaf be too much?

    • Reply Mari May 21, 2016 at 9:23 pm

      I do think it’s possible to put in too much but I don’t think one leaf would be too much of a problem. Sorry for the late reply, hope it worked out for you!

  • Reply Candy May 3, 2016 at 4:53 pm

    Hi do you usually boil your leaves before putting them in the rank or just add them from the bag? Thank you

    • Reply Mari May 5, 2016 at 10:58 am

      I just add them from the bag! If you buy leaves for aquarium use they should be pesticide free and 100% safe. As mentioned in the article you can boil them to make blackwater extract, though.

      • Reply Candy May 5, 2016 at 11:37 am

        Thank you!

  • Reply Julia Lusk March 14, 2016 at 11:09 am

    Hello I have a 31/2 gallon tank with one betta .. Would half a leaf be plenty for this size. He is completely happy and healthy but I thought he may still benefit from the almond leaf.

    • Reply Mari March 14, 2016 at 11:14 am

      1/2 or one leaf would probably be enough, yes. I’m not really a fan of keeping bettas in such small tanks, though!

  • Reply Elise February 16, 2016 at 12:56 pm

    In my 10gal tropical community tank others fin rot. I have 1 male betta 4 corys and an otocinclus. I hate using medications and was wondering how well Indian almond leaves work for fin rot. And how any do you put in a 10gallon to treat fin rot? It’s not server yet but bad enough. Thank you!

    • Reply Mari February 16, 2016 at 8:39 pm

      Hi! What kind of Cories do you have? It sounds like your tank may be a little overstocked which is likely causing the fin rot. I’d recommend rehoming at least one species – if the cories are anything other than Corydoras pygmaeus, hastatus or habrosus then it’s really a good idea to find another home for those. You can then expand your group of Otocinclus, they prefer to be with at least four or five and don’t have a very high waste output.

      As for treating fin rot with these leaves, they don’t replace medication but can help if there is no very serious damage yet. Beginning fin rot can be treated with a combination of very clean, warm water (daily water tests with your liquid test kit, increase your water changes) and possibly some Indian almond leaves. Three leaves would be a good starting point, don’t be scared if they discolor your water. If the fin rot keeps progressing you’ll unfortunately likely have to switch to antibiotics. However, as the fin rot is likely caused by overcrowding I suspect you won’t have too many problems with it once you’ve rehomed a few fish. 10 gallons is very small and can only be stocked very lightly!

      Good luck! I hope everything turns out alright.

  • Reply Jack February 15, 2016 at 9:06 am

    Hi, can I use it to lower PH in Aquaponics?

    • Reply Mari February 15, 2016 at 9:40 pm

      Hi! Although Indian almond leaves can help lower your pH a little, I wouldn’t rely on them if you really want to work on your pH. As with stuff like wood, the effects likely won’t be too drastic. Using RO water might be helpful if you really want full control, though reading a few guides is definitely a good idea before getting into it 🙂

  • Reply Trepkos December 25, 2015 at 8:21 pm

    How long do these take to work? We put some in our 6 foot and 4 foot tank about a week ago (7 and 5 leaves respectively) and haven’t seen any change. If it takes weeks, then presumably every time we change water, (one per week) we will be working against them.

    • Reply Mari December 26, 2015 at 9:51 pm

      Hi! The leaves start working quite quickly, but with 6 and 4 ft tanks I think you’ll need a few more than what you’ve used now! Looking into oak leaves, alder cones and almond leaf extract might help as they all have similar blackwater effects 🙂

      • Reply Trepkos December 27, 2015 at 2:03 am


  • Reply Blackwater Aquariums | The Aquarium Guide November 20, 2015 at 11:01 pm

    […] can achieve the blackwater look in your home aquarium using leaves (Indian almond or oak), driftwood, or alder […]

  • Reply Joseph November 6, 2015 at 12:38 pm

    Can I use Indian almond leaf along with API stress coat water conditioner?

    • Reply Mari November 6, 2015 at 12:39 pm

      Yes, you should be able to combine them with normal aquarium products 🙂

  • Reply Ash October 16, 2015 at 5:48 pm


    Can I use them with my snakehead?

    How many leaves per litres of water?

    • Reply Mari October 17, 2015 at 10:54 am

      Snakeheads naturally live in low to neutral pH waters, so I think it would work fine! I assume you have a pretty huge tank for a snakehead, so you would need quite a few I think. Maybe start with 1 leaf per 5 gallons (20L) and see how that works for you? 🙂

  • Reply Ramon October 6, 2015 at 12:30 pm

    Can Almond leaves be used in an Angelfish breeding tank with fry in it. I have a breeding tank with fry and want to use these if it’s okay.

    • Reply Mari October 9, 2015 at 10:26 am

      I think that would be okay! Angelfish are naturally from stained waters so it would help imitate their natural habitat.

  • Reply Quinn September 12, 2015 at 11:23 pm

    Is there still benefit to use with carbon? I have one 4 inch leaf and a small amount of carbon in 100 litres and so far no colour. Fish Inc tetras, Cory and shrimps.

    • Reply Mari September 13, 2015 at 10:09 am

      I think the shrimp like to eat the leaves, but other than that there is no benefit if you’re also using carbon (unless it has already lost its effectiveness, which doesn’t take too long). In a 100 liter, one leaf isn’t going to do much, though, you’ll definitely need to use a few more to actually see a difference. Good luck!

  • Reply Justin August 13, 2015 at 10:33 am

    Have you used these leaves with Goldfish? I am wondering if it would be good for them as a natural defense for fin rot

    • Reply Mari August 13, 2015 at 12:24 pm

      I haven’t! I mostly use them for fish that prefer acidic water, like bettas, gourami or corydoras. Goldfish prefer a slightly higher pH which may lead to issues.

  • Reply Emily May 22, 2015 at 9:29 am

    Got mine from , was wondering if there’s any different if the leaves came from different country????

    I love the aroma , they came from Malaysia. because the last time i bought from another country they were broken. and smaller.

    • Reply Mari May 22, 2015 at 5:39 pm

      I don’t think there’s any difference, they should be fine! I personally don’t mind smaller broken up pieces, but if these work for you there’s no need to worry about anything.

  • Reply Mandy March 11, 2015 at 12:48 pm

    I was wondering if these leaves can be used in a tank with orange and blue neon tetras, black phantom tetras, corydoras, albino rainbow shark, and upside down catfish. There’s no aggression in the tank and I don’t want to cause any sort of distress which might lead to aggression.
    I’ve had live plants in my tank before but the fish started to eat the plants and that killed the plants. Is it safe for fish to eat the leaves? Once the leaves start breaking down do they release any sort of ammonia?
    Thanks for your time and help,

    • Reply Mari March 11, 2015 at 10:15 pm

      I think you could use the leaves if you want to; they do of course release some wastes while breaking down, but you should not experience any problems. Many people actually let them break down completely, but if you’re unsure you can remove them timely to prevent any possible issues. You could start with one leaf and see how it works! You can also use almond leaf extract so you don’t need the actual leaves.
      I’m just wondering how big your setup is, though? The sharks especially need a very big tank and are semi-aggressive, so unless your setup is quite big there may be aggression in the future.
      Good luck!

  • Reply lisa September 10, 2014 at 7:25 pm

    Well, I am definitely getting these. A few quick question- How do I tell if they could be carrying a disease, or something that could harm my fishies?
    And would neon tetras like these? I know they come from slightly more acidic water, and don’t think they would dislike them, but I do want to check.

    • Reply Mari September 15, 2014 at 8:01 pm

      If you order from a trustworthy site you can be 99% there are no pesticides/diseases on the leaves! I have never had problems with it. Neon tetras do like Indian almond leaves, so you can definitely try them if darker water is not a problem for you 🙂

      • Reply Lisa September 20, 2014 at 7:02 pm

        Great, Thanks! Darker water is not a problem for me, as I think it looks sort of pretty when you are doing certain aquascapes. My fish will have to wait a while before I can get them(I’m thirteen, and my parents don’t believe in buying stuff like this, so I have to wait until Christmas) Hopefully by that Time I’ll have had my Divided betta tank set-up, so all my bettas can have IAL, as well as my neons.

  • Reply Paolo August 18, 2014 at 2:13 pm

    Hi there! I just want to say that I love your blog so much and ive been following you ever since it was just your goldfish tumblr. I’m from the Philippines and indian almond trees grow everywhere, i would just like to know if there is any actual difference between handpicked and dried leaves and naturally dried leaves because there seems to be conflicting opinions online and id feel much more comfortable asking you hahaha. Thank you so much!

    • Reply Mari August 19, 2014 at 8:35 pm

      Hi! That’s actually so great to hear, thanks for messaging me!

      I’m actually unfortunately not sure if there is a difference, although I don’t think so. I think I’ve used both and I’ve never noticed any difference. Just be sure to pick the big “adult” leaves and I think handpicking is fine!

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