My mangrove obsession, and the basics of Mangrove care.

I admit, I am not the go-to authority on anything about aquatic plants.

In fact, you'll be best served by asking anyone- like, your non-aquarist neighbor, the dog groomer, or even the barista at your local coffee house- questions on aquatic plants before you think of asking me for advice on them! This should hardly come as a surprise to those of you who know me personally! I'm not known for lush, pristine-looking, meticulously-planted aquariums! 

I have kept plants many times over the years. My current home "Asian-themed" blackwater aquarium actually has aquatic plants in it- but they fail to ignite my passion for some reason. Yet, I don't know a Riccardia from a Riccia. And it doesn't really bother me. I appreciate aquatic plants. I enjoy looking at planted tanks...They just don't make my heart skip a beat with excitement. "Estimative Index", "Dry Start", "Walstad Method?"

Might as well be speaking another language.

Yeah, that's my "jam" on aquatic plants.

That being said, there is one "plant"- well, a tree, actually that grows in aquatic environments, which I have become obsessed with over the years...The Mangrove.

Specifically, the "Red Mangrove", Rhizophora mangle. The one we'll focus on here and refer to as "Mangrove" for the purpose of this piece.

Hardly what you'd call an "aquarium plant"- I mean it's a tree.

That being said, the Mangrove is an amazing tree that certainly has applications for aquariums- specifically, brackish aquariums. Now, without going into a long, long, recap of what mangroves are and how they function (You can Google this stuff and get hundreds of hits with more information than you could ever want), let's just say that mangroves are a group of trees and shrubs which live in the coastal intertidal zone, in areas of warm, muddy, and salty conditions that would simply kill most plants.

They possess specialized organs which allow them to filter out sodium, absorb atmospheric air through their bark, and generally dominate their habitats because of these and other remarkable adaptations.

There are about 100-plus different species, all of which are found between tropical and subtropical  latitudes near the equator, as they are intolerant of cold temperatures. Mangroves put down extensive "prop roots" into the mud and silt in which they grow, giving them the appearance of "walking on water." These root tangles help them withstand the daily rising/falling tides, and slow the movement of the water, allowing sediments to settle out and build up the bottom contours of the local ecosystem.

And of course, the intricate root system not only protects coastlines from erosion, it plays host to a huge variety of organisms, from fungi to bacteria to crustaceans to fishes. The fishes use mangrove habitats as a feeding ground, nursery area, and a place to shelter from predators.

Okay, you get it. But how do we use these trees in the aquarium. And wait a minute, you're talking about a tree? WTF?

Well, yes. I am. No, fist off, before you part going off on me about their unsuitability for aquariums or some ethical implications for their "removal" from the wild, let's talk for a second about how we acquire them and how they grow. First off, removing a growing mangrove tree or seedling from the natural environment is unethical, illegal in most areas, and essentially idiotic.

NO one should even consider doing that. Period.

Rather, we acquire mangroves as propagules- buoyant seedlings which grow through the fruit, and can produce its own food through photosynthesis. When the propagules are mature, they fall into the water, and can remain in a dormant state, withstanding desiccation, for more than a year! Propagules are buoyant and can float until they find suitable "anchorage." When it's ready to take root, a propagule will change its internal density to float vertically, rather than horizontally, to make it more likely to root in suitable sediment. 

As aquarium people, we start with these free-floating propagules, which are abundant and legal to collect in places like Florida, where the adult plants are protected from harvest or pruning. The advantage of propagules is that they can be stored in a moist environment and easily shipped in damp paper towel, and stored that way for extended periods.

So, once you have one of these pickle-like propagules, how do you use it?

First off, you don't need to "root" it, or "plant" it in substrate. You simply need to anchor it in the water column in a vertical position, and allow it to extend roots down towards the bottom on its own pace. I have typically done this in relatively small containers of water, like a jar, vase, or pitcher, before translating it to the aquarium. 

You'll know that the propagule is ready to transplant when it becomes a "seedling"- with little roots showing up on the bottom, and leaves beginning to unfurl on the top of the propagule. You can sprout the propagules in all sorts of light conditions- typically even room ambient lighting (as in a windowsill) will do the trick.

Fluorescent, LED, or other aquarium-rated "daylight" lighting will accomplish this, too. Of course, the part with the leaves needs be anchored above the water line (yeah, people ask me this question regularly). Like everything we do in the "natural-style" aquarium game, patience, diligence, and observation are essential when keeping Mangroves.

If using an artificial light source, be sure to mount the light well above the container or aquarium where the mangroves are kept. This not only results in a more natural-looking growth form- it keeps the leaves from growing literally right into the light and frying themselves (I've done that many times, lol).

Once they are placed in the aquarium, you should anchor them near the water surface, not in the substrate. As discussed many times before, I've chosen to attach my propagules to (legally-collected) mangrove root pieces in my brackish- water aquarium, and that works really well.

Allow the roots to "find' the bottom for themselves. This will encourage the growth of a strong, almost "woody" prop root system that these trees are famous for. It may take many months for them to achieve "touchdown and penetration" into the substrate, but they will- and a stronger plant ensues as a result of allowing them to do it themselves!

One little word of advice: Be sure to sprout your mangrove propagule in the same water conditions (ie; marine, brackish, fresh) as you will be keeping them in perpetuity in your aquarium. They categorically don't adapt well to habitat changes once they have begun to grow.

Now, what kinds of substrates should you use? Well, keep in mind they come from muddy, sedimented, nutrient-rich environments in Nature, so they can handle just about anything. I've personally utilized everything from marine biosediments to aragonitic sand, to mixes of pond soil or aquatic plant soils. You can mix in peat and all sort of substrate enhancement materials to provide sustenance and proper rooting for these hardy trees. A little online research can yield lots of great tips on substrate mixes for mangroves in the captive environment.

The beauty of mangroves is that they're pretty hardy- which bodes well for their care in the aquarium! You need to do little more than illuminate them, anchor them in a vertical position above substrate, and mist the leaves on a regular basis. This process helps to keep dust, salt build-up (which is exported via the leaves), and insects off of the leaf tissues.

Now, again, we'll often hear arguments that keeping a tree in an aquarium is kind of crazy. I admit, a full-grown mangrove tree is virtually impossible to keep in a home aquarium. However, these trees grow incredibly slowly, reaching "houseplant-like" sizes after a year or more in captivity. And, with frequent pruning, you'll see that they can be maintained in almost a "bonsai-like" size indefinitely- all the while putting down the extensive, intricate  root systems that they are so famous for.

One of the cool benefits of mangroves in the aquarium- much as in Nature- is that their roots will recruit and foster the growth of microorganisms, fungi, algae, and other epiphytic life forms, providing a foraging place for fishes, and the ability to contribute to the biodiversity and healthy function of your aquarium ecology.

In addition, the "leaf drop" which mangroves are known for accomplishes the same thing it does in Nature: Helping to provide leaf litter, which encourages the growth of microorganisms and other life forms, and tinting the water via exudation fo tannins and humic substances. As you might guess, I encourage the fallen leaves to accumulate and decompose in the aquarium! 

Notice I don't talk about utilizing mangroves as a "nutrient export" mechanism in your aquarium? This is because it would take many mangroves (like, more than your tank caudal accommodate) over many years to provide any noticeable nutrient export effect on your tank. Rather, we choose to focus on their unique aesthetics and their ability to foster the growth of other, beneficial life forms.

Sure, we could probably go on and on about keeping mangroves in your aquarium (and probably will again I the future), but I hope that this admittedly superficial "quick start" guide will encourage you to research more about these remarkable trees and try them in your aquarium. 

If you're fascinated by these amazing, adaptable trees, can obtain them legally and responsibly, and are up for the challenge of keeping them over the long haul, mangroves are a fascinating and attractive addition to your specialized natural aquarium! 

Until next time...

Stay curious. Stay patient. Stay resourceful. Stay diligent...

And Stay Wet.

 

Scott Fellman

Tannin Aquatics 

 

 

 

 

 


Scott Fellman
Scott Fellman

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12 Responses

Greg
Greg

April 23, 2021

Good to know and thanks for the information regarding getting the red mangrove propagule to root. Agreed, pushing these red mangroves “pencils” into the mud does not work, at least here in the Tampa Bay Area.

We have a mangrove forest/“reef” of about 8 acres in upstream estuary habitat on our ranch but it seems overcrowded with black mangroves – which are good, at least from our bees’ honey production and the wind protection the blacks afford from tropical storms. However the black mangroves grow so thick together the reds seemed crowded out in many places where they should grow. We have no shortage of red propagules floating around though.

Our main concern though is removing Brazilian Pepper trees as they compete well and will displace mangroves of all breeds here ( including the whites and buttonwoods).

Greg

Dani
Dani

April 10, 2021

Love this article and the pictures. I’ve recently purchased some sprouted (by the seller) red seedlings online for my freshwater tank after looking into them for a while and reading about growing them in freshwater. They were sprouted in saltwater according to the seller but I didn’t read that till after they arrived because I was too excited to find them in stock for that price at the time lol. Since they were here already, I crossed my fingers and put them in my tank with styrofoam floaties. They seem to be doing well, already growing new leaves and old leaves still look great. I’d attempted a few black ones a couple years ago but didn’t have the proper set up, plus a couple mishaps, and failed. So I managed to get some more this year and going to try again.

Scott Fellman
Scott Fellman

February 18, 2021

Hi Joan,

I’d use very rich substrate. You could use stuff like pond soil a=mixed with sand and other materials to create an almost muddy, but rich substrate. The key is to keep it from making a mess, lol. It takes a while for mangrove propagules to establish. The roots need to “find” the soil. It can take many months. If you’re starting with seedlings which already have roots, you can place them gently into the substrate.

Joan
Joan

February 17, 2021

I just got two 3’ tall red mangroves for my pond that have been raised in fresh water. Curious about how fast I can expect the roots to grow. I’m thinking my best bet is to section off part of my pond as a bog and plant them directly in it instead of keeping them potted. If that makes sense, what mix of substrate would you use?

Scott Fellman
Scott Fellman

January 11, 2021

Hi Scott- Sounds like an exciting project! One of the important things about mangrove cultivation is (IMHO) to start with propagules, and sprout them in the same type of water (ie; brackish in your case) as you intend to maintain them in. Mangroves categorically don’t do well wen you switch them rapidly from pure fresh water to brackish or full-strength marine water, so starting them as propagules is really important. I’m not a fan of obtaining established plants, especially if they’re rooted in substrate, and if your intent is to start them emerged in your tank or system. You certainly can, you just have to go very slowly.

Your idea sounds pretty good! The only change I’d make is with the substrate mix. I’d omit the gravel, and just opt for sand over your richer substrate mix. Typically, you’ll find mangroves rooted in mud, silt, and sand; they’re generally not found in more coarse substrates.

My fave approach with mangroves is the slow way, lol. I’d obtain some propagules (many local fish stores can obtain them for you, and there a number of online purveyors, including places eBay and Amazon which can sell you propagules. They should be rooted in the type of water that you ultimately will be keeping the trees in (ie; brackish), and as they begin to establish themselves, they’ll slowly put down prop roots, which will eventually “touch down” in substrate. As they begin to put these roots down and put out branches, you’ll be able to transfer them to a more permanent setup like your pools. Good luck!

-Scott

Scott Fellman
Scott Fellman

January 11, 2021

Hi Don,

The optimum way to keep your mangroves healthy and happy is to make sure that they are getting plenty of light and nutrients, like any other plant. As they naturally put down their prop roots, they should be rooted into a very rich substrate; ideally, something like a mix of sand and perhaps poqtingsoilor pond soil. Spray the leaves off regularly to keep dust and exuded salts from accumulating on the leaves. There’s actually a surprisingly large amount of information on the basics of mangrove care out there on line, so do some googling and you’ll likely find some good stuff! -Scott

Don Pramis
Don Pramis

January 09, 2021

hi man! I also love mangroves have some question how to make leavea greener..

Thanks

Scott R
Scott R

January 08, 2021

Scott,

Awesome work, I love the podcast and the blog. Shortly after your interview with the Aquarium guys I started listening to your podcast and adding botanical all my tanks in varying degrees. Living in South East Texas, I am very fortunate have access to lots of hardwood trees on a friend’s land. I even have two Narrow leaf Live Oaks in my front yard, plus the most of the local fish stores in Houston keep the common leaves, pods, and cones for use with shrimp.

I am planning on setting up 2 brackish pot ponds (20 and 65 gallon) with Red Mangroves just before spring. I have had a few small pots for 2 years, and I have one freshwater with the local mosquito fish (Gambusia Minnow) that survived our mild winter very well this year. I am planning a soil / mud bottom with a gravel and sand cap, with local rocks, wood, and leaves. I will be adding Nerites and maybe some local brackish shrimp. It will be positioned to allow for some shade during the day. I will be testing the PH, but I am expecting 7.5 to 7.8, since the local water PH is high and am not doing RO. If the ponds go well this year would like to try some type of killifish in them maybe next year. I think this system needs to be stable and aged before I try killifish.

I would love to have any comments or suggestion, especially on the sources for Mangroves or maybe possible annual brackish killifish (started following the AKA group on FB recently).

Thanks,

Scott R, FishFool in the Aquarium Guys Discord

Scott Fellman
Scott Fellman

September 19, 2020

Hey Tracy,

Thanks for the kind words. Glad you found this article helpful… SO much more to learn about them…I hope you enjoy your first foray into them! The more hobbyists play with them, the more we’ll all learn to appreciate their amazing qualities!

-Scott

tracy
tracy

September 18, 2020

Just got my first two mangrove propagules ever. This was a very informative post – thank you for sharing these instructions and your experiences with this amazing tree.

Scott Fellman
Scott Fellman

May 25, 2019

Hmm…this one sounds to me like some sort of fungus or something. I couldn’t really tell you exactly what it is….Might recommend consulting a houseplant care guide. I’d move the mangrove away from other plants, and even manually wipe or spray the leaves down with a very mild, diluted household detergent solution (done this on houseplants/vegetable plants many times in this situation)…But that’s my best course of action from experience…I’d really consult plant experts on this one! Good luck…Scott

Kristi johnson
Kristi johnson

May 25, 2019

Have a mangrove in water – house plant – but leaves are getting sticky – and the stickiness seems to spread to other areas of plants on the same windowsill.
Water is brackish – but read not to disturb roots. Would like guidance.

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