Beyond the botanical: Along came a...Kurrajong Pod!

When we curate botanicals for including in our collections, we look at stuff like the overall "utility" of the botanical  it's ability to affect the physical environment of the aquarium  and yeah, how it looks! Periodically, we'll stumble on a botanical that not only "checks all the boxes"- it tends to become an interesting "staple" to our botanical-style aquarium "practices" along the way.

Either the Kurrajong Pod.

This unique pod comes from the Kurrajong, or "Bottle Tree", Brachychiton populneus. These pods have a nice little opening and a hollow interior cavity that is just large enough for small fishes or shrimp to hang out in! I suppose it's what you'd end up with if you crossed a "Jungle Pod" with a Cariniana Pod! 

Well, maybe.

The Kurrajong Tree is native to Victoria, Queensland, and New South Wales in Australia. However, it has been distributed as an "ornamental" tree throughout the world because of it's hardiness and noteworthy drought resistance. In fact, the tree utilizes its extended trunk as a water storage "device" for survival in a warm dry climate. In fact, the aboriginal tribes of Australia discovered millennia ago that water could be obtained from the tree roots by boring a hole in the trunk and squeezing the wood, making it an important supplemental resource in arid climates!

And of course, the Kurrajong Tree's usefulness doesn't end there. It has been noted that the seeds located in a seed pod were often removed and cleaned of the fine hairs within the seed pod (more on these little bastards later...) and were often roasted and eaten. And it was also documented by researchers that the seed pods themselves were used as rattles for children! I love the resourcefulness of these indigenous people- nothing is wasted.

Sometimes Brachychiton populneus is also known by the names "Lacebark Kurrajong" and simply as "The Bottle Tree"- particularly in North America, where they are often employed as ornamental trees in parks and other open spaces as part of the landscape.

Originally classified in the family Sterculiaceae, which is now within Malvaceae, it's an evergreen tree, which grows up to 40 feet (12 m) in height. They flower in late spring, and this event is followed by the appearance of the woody, brownish seed pods that we treasure so much!

As mentioned before, these pods contain seeds that are covered in stiff hair that penetrates the skin and hurt like a mother------! In fact, the genus name Brachychiton comes from two Greek words, meaning "short", and "tunic", an allusion to the bristles surrounding the seed in the fruit! (for those who must know, the species name, populneus, comes from Latin and means  "poplar-like"; as the the leaves resemble those of Populus species.)

Fortunately for our customers, we go the extra mile and make the effort to remove the seeds from the pods before we offer them for sale. It's an important and rather prickly practice, but it ensures the safety and usefulness of the pods for our purposes!

They're super nasty little seeds, but easy to remove. It's just a pain, but I've actually gotten pretty good at it over time.

Now, the preparation for these seed pods doesn't stop with the removal of the little seeds...These are "super lightweight" pods, yet have a hard, woody exterior, and will require some boiling to get them to saturate and sink. Usually, this can be accomplished in about 45 minutes or so.

They might occasionally "close up" a bit over time after submerged, but the opening is easily pried back open with a tweezers. They tend to darken up, yet last a good long time, holding their unique shape for many months, in my experience.The specimens in the pic below were in one of my tanks for about 4 months when they were removed for this pic...

Like many of the botanicals we offer, they have what I like to call "generic botanical flexibility"- another one of my fun, made-up expressions for something that is a great stand-in for materials which you might find on the substrate in any tropical aquatic habitat. Small fishes and shrimps tend to use them as a foraging area and even as a little "cave" to hide in.

The likelihood of these particular botanicals ever being actually found in an underwater habitat is probably next to nil. It is frequently found in dry scrub areas and occasionally extends into the edges of the nearby rainforest. Although, according to at least one description, it occurs, " the upper catchments of rivers and on rocky hilltops" throughout its range, it seems unlikely to me that you'd find these pods in water where tropical fishes reside in nature.

(Image by Philmarin, used under CC BY-SA 3.0)

That being said (and now that I burst your bubble), I think that these are really cool for our purposes!  That little "taco shell" opening has a certain appeal for small fishes, and the overall look of these botanicals definitely adds a little "something" to your botanical-style aquarium!

Until next time...

Stay curious. Stay smart. Stay experimental. Stay creative...

And Stay Wet.


Scott Fellman

Tannin Aquatics 







Scott Fellman
Scott Fellman


3 Responses


October 11, 2022

Yes!! I use these in my shop for early childhood exploration, and indeed, cleaning them can be a painful endeavor! I have to get them extra clean too, seeing that kiddos will be handling them. I actually read the article hoping to gain an easier approach to removing the fiber glass like hairs, but I get why it wasn’t included. Maybe we could share tips via email😉
Also, they can be molded into any shape when wet. Then, using a rubber band or tape to hold until dry, will retain the shape. I would think that maybe being positioned in the right place (pushed vertical into a small space) could prevent them from ever closing. Just any idea!
Although not what I was looking for, I enjoyed your article.

Scott Fellman
Scott Fellman

January 24, 2021

Sounds awesome! it really amazes me how botanical materials from anywhere I the world can function. in the same manner as the “local” materials found I the habitats where our fishes hail from. As you learned, and as others are finding out- our options are virtually unlimited if we’re willing to experiment. And the same processes which govern the decomposition of a leaf in the Amazon do the same with an Australian seed pod! Really cool stuff!


Dave Watson
Dave Watson

January 23, 2021

Great article. I’ve just established my dream 2,700 litre Rio Negro feeder creek biotope aquarium, and I’m using Brachychiton leaf litter to add tannins and microhabitats, using shed leaves from several trees growimg on our property (in southern New South Wales). What I wasn’t expecting—the fish love it! I have a group of 13 young Uaru who soend their days chowing down on the decomposing leaves, and a mob of seven Metynnis sp aff maculatus is also chowing on them (but seems to be grazing on the biofilm growimg on them. So yes, two thimbs up for these trees, the Antod an analog of the stately Ceiba trees that frimg the Amazon

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