Leaf "Geek Out": In praise of Jackfruit Leaves!

Sometimes, it hits me how incredibly geeked-out I am about the idea of playing with leaves and stuff.

As a reef aquarist for decades, and someone who co-owned one of the more successful and best-loved coral propagators in the U.S., it makes me smile when I realize that I've brought the same level of geekiness to something as esoteric as "twigs, nuts, and 'dirty water' aquariums" (as one of my reefing buddies gleefully pointed out) and have built a business based on this weird obsession! I mean, I can talk for hours about this wierd stuff!

As you know, it's kind of an ongoing mission of ours here at Tannin Aquatics to seek out, research, and experiment with all sorts of botanical materials and leaves in our aquariums. Over the first few years of our existence, we've been privileged to have access to a variety of botanical materials which have not previously been used in aquariums. And more so, privileged to have played a small role in the emergence of this "New Botanical" movement of "Blackwater Aquariums, V. 2.0" that's sort of...well- exploding right now!

Every one in a while, I have to highlight some of my favorite botanicals- not out of some self-serving desire to push what's hot, or not selling, or whatever...Rather, to celebrate, elevate, and share my love of some of them with you, "Tint Nation", because they're so damn cool!

And because, as my wife says...I'm a geek.

So be it. :)

When it comes to leaves for aquarium use, I have tried quite a few, and one of my faves has to be the leaves of the Jackfruit tree (Artocarpus heterophyllus).  

Now, these guys just don't seem to get the same level of devotion, attention, and love as the more "trendy" leaves, like Catappa and Guava (lol, "trendy" leaves- I HAVE truly lost it...), so I thought I'd share my love for them with you today! Now, this tree is very common in some parts of the tropical world, and the fruit and leaves have been utilized as a food and used in traditional medicines for centuries. They are particularly abundant in India, and that's where our story begins. Jackfruit trees are often found overhanging rivers in India, dropping leaves into the water, and of course, imparting a brownish tint as they decompose!

They have been used by fish keepers in India to impart tannins into their aquarium water, much in the way Catappa, Guava, or other leaves are. A friend of ours, author/photographer/awesome fish breeder, Sumer Tiwari, told us they work great with his killies and Dwarf Cichlids! And if you've seen his award-winning fishes, you'd give this a lot of thought! As lovers of aquatic botanicals, and leaves in particular, I was immediately interested, of course, and was able to lock down a terrific source for these unusual leaves, and began playing with them in my own tanks. Dutifully impressed, we released them for sale to you, where they have become a "regular" in our repertoire of botanical goodness! And to our knowledge, they hadn't really been available regularly outside of their native region for aquarium use before, and we were, of course, thrilled to be able to offer them to hobbyists!

Jackfruit itself contains phytonutrients, such as lignans, isoflavones, and saponins that have health benefits that are wide ranging for humans. There is some conflicting data regarding jackfruit's antifungal activity. However, the leaves may exhibit a broad spectrum of antibacterial activity. In traditional medicine, these leaves are used to help heal wounds as well. Now, this is sort of similar to the attributes ascribed to Catappa, and there is probably a lot of "wiggle room", in terms of what they really can do and what we'd like them to do! And, as we've said before- what some of these materials can do for humans, they may not necessarily do for fishes.

That being said, there are some things that we are aware of- mainly that they are durable, attractive leaves, which definitely can impart tannins into the water, giving it a nice tint! As mentioned above, we are not aware of any scientific studies that have been completed to correlate "medicinal" or "prophylactic" benefits of Jackfruit leaves specifically- to fishes or shrimps, one way or another- so for now, we're content to utilize these leaves for their aesthetics, biofilm "recruitment", durability, and proven ability to impart a tannin "tint" into aquarium water!

We do know that many of the chemical compounds contained in the leaves, as outlined above, are similar to those contained in Catappa leaves, and studies done on Catappa leaves do indicate some potentially anti-fungal properties...so... yeah.

These are nicely-shaped, high quality leaves that bring a very nice "tropical" aesthetic to the aquarium, as well as that tint we love so much around here! Jackfruit leaves look amazing as part of a mixed litter bed, and is "strong enough" aesthetically to stand on its own, too! They will last a pretty long time- not quite as long as Magnolia, but longer than Catappa and Guava, in our experience.  And they hold their shape really nicely, sink rapidly, and stay down- all prerequisites for successful deployment underwater in an aquarium!

I'm currently using a significant quantity of them in my new home aquarium, along with some small Catappa leaves and Yellow Mangrove Leaves, and I'm happy to report that, after over a month and a half submerged, they're almost as "solid" as the day they were placed in the tank! They will recruit biofilms on their surfaces, which, as most of you know, ornamental shrimp love to feed on (as well as consuming the leaves themselves as they soften). I see my characins, dwarf cichlids, and small catfishes "grazing" continuously on their surfaces, making them a great candidate for any mixed leaf litter bed, IMHO!

Although collected in an area that is free from pesticides or other contaminants, it's just good common sense to prep Jackfruit leaves before using in your aquarium. Our "Aquatic Botanical Preparation" section on the site has a lot of information on what we've found to be "best practices" concerning the preparation of botanical materials for aquarium use, so please do refer to it-and feel free to update us with your experiences as well! As with the other leaves we offer, we recommend that you rinse and/or steep them in boiling water before use, and add them gradually to your aquarium, so that you can gauge for yourself the impact they have on your water. Our experience shows that they have a "tint capability" somewhere in between Guava and Catappa, although your results may vary, of course. This is a highly scientific assessment, of course (tongue firmly planted in cheek...)

As we've mentioned so many times in our blogs, the practice of adding terrestrial dried leaves and other botanicals to our aquariums for the purpose of influencing the environment and health of our beloved fishes is growing and evolving daily. We're learning the good, the bad, and the erroneous attributes and implications of our craft. Sometimes, it's just nice to take a minute or two to look at the materials that we've already had at our disposal, so that we can get a better picture of how they might fit into our next aquarium setup! (or vivarium or paludarium, as well! ).

If you have any cool pics or experiences with Jackfruit leaves that you'd like to share with our community, be sure to let us know!

Stay interested. Stay experimental. Stay creative. Stay bold!

And Stay Wet.


Scott Fellman

Tannin Aquatics


Scott Fellman
Scott Fellman


2 Responses

Scott Fellman
Scott Fellman

December 24, 2017

Hi Dave,

I agree with you in many ways that leaves have more properties/capabilities that we might fully understand! I LOVE that you’re experimenting with many different leaves. I think that there are many. many leaf types that aren’t currently used in the trade that will impart similar characteristics as catappa into the water. In your region, Teak might be an interesting leaf to play with. Your country is blessed with an abundance of leaves to experiment with. I am not aware of any specifically ichtyotoxic leaves; however, I’m afraid it will take some experimentation to really get a good indication of that. All in all, I think most leaves not known to be toxic to humans seem to work fine with fishes, although that’s a sort of sweeping generality! Keep us updated!


David Boland
David Boland

December 23, 2017

Enlightening article! I’m going to collect jackfruit leaves and guava leaves tomorrow to start experimenting with their water tinting properties. I have been using Catappa for its comforting medicinal benefits to Labyrinth breathers. I personally feel that Catappa also has properties of transforming raw water into fish conditioning cured water in much less time than what it otherwise would take in an ammonia nitrification cycle. The Catappa seems to naturally harbor and nurture beneficial bacteria and the necessary probiotics, enzymatic activity and pH maintenance attributes that fish need to thrive, in an otherwise artificial environment. I also believe that these tannins released into the water are capable of healing wounds and toughening scales, skin and slime coat of many fishes.

I have a short list of leaves that I want to experiment with that already have known healing properties for humans that may benefit fish as well. Are you aware of any large leafed botanical that is directly harmful to fish that I would need to stay away from? Are you curious to know the result of other known Botanical leaves from the Fauna of tropical jungles? I’m already finding that it’s not all leaves that release tannins well into the water. I’ve also found some evidence of tannins leaving stains on the skin and scales of what should have otherwise been a very white ornamental fish.

I would love to hear any feedback or any comments and suggestions on what studies or amateur experiments I could conduct with various tropical leaves.

Thank you for your article,

Dave Boland
Sukhothai, Thailand

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