In pursuit of shiny brown objects...

Hello, enabling fish geek friends!

Thanks to a bit of prodding from you, our "Tint Nation", I've pulled the trigger on a couple of new additions to our botanical-style brackish aquarium!

As you know, I've been extremely picky about creating a collection of fishes that, while geographically ridiculous, are all species associated with, or found in actual brackish water habitats in the wild. It hasn't been as easy as one might think! So far, we've kept the Rainbowfish Pseudomugil cyanodorsalis, a group of Bumblebee Gobies (Brachygobius sp.) collected from a documented brackish-water habitat, and...yeah, a domesticated form of Molly that a friend  sadly collected from a brackish water estuary near his home in Louisiana. (Yes, kind of cheating, I know...but when I saw these guys I kind of liked them!)

It's been a sort of weird process, I admit. And the stocking plan is basically whatever I can find that fits my "requirements", I suppose.

The idea was to create a collection of species which are small, interesting, and are actually from brackish water. There is a lot of misunderstanding and confusion about some "old faves", like "Glassfishes", long regarded as fishes that come from brackish habitats, when the reality is that the vast majority of the ones collected for the hobby come from pure freshwater, even acidic, habitats! 

And it goes on and on...Once you get out of the hobby literature and look into the scientific literature, it turns out that many of the fishes we have labeled as "brackish" might, might have populations which are found in brackish, but the bulk are not from this type of environment. I'm part fish geek- part "myth buster."

And there are a lot of "myths" out there.

So the search isn't as easy as one might think! There are a bunch of actual brackish water fishes out there in the hobby, but the bulk of them are either domesticated variants of wild species, which can work because of their euryhaline capabilities. Fewer still are actual brackish water fishes; many are simply not collected for the hobby for a variety of reasons, not the least of which is that the bulk of 'em are kind of dull, to be quite honest.

You have to really be into this to find "real-deal"  small brackish-water fishes, and even more hardcore to create a tank of brackish fishes from the same geographic location. It's taken me almost a year just to aggregate the few, wildly geographic- ranging specimens that I have. 

Recently, through peer pressure, I was able to bid at auction on a few pairs of a cool fish- the rather uncommon "Swamp Guppies",  Micropoeceila picta! This is a fish that, although rather uncommon and somewhat challenging to obtain, has been on my "short list" of fishes I wanted to keep for some time. There is something satisfying and compelling about finally nabbing the fishes you've been pursuing for a while, huh?

This is a livebearer that is known to come from brackish water swamps, mangrove thickets, and marshes. It's a small fish, maxing out around 1 inch in length. The males have an interesting red-orange body with contrasting black markings, while the females are regulation-issue "Livebearer Silver" (ie; essentially colorless). And of course, they reproduce relatively easily because they're livebearers.

Geographically, they hail from Central and South America, from Trinidad to the Amazon River Delta. This means they're found in Brazil, French Guiana, Guyuana, and Trinidad and Tobago. So, a wide geographic region, giving you a bit of "latitude" if you're hell-bent on being biotopically accurate!

The specimens that I am obtaining were kept in 1.010 specific gravity, which is right where my tank is, so acclimation after quarantine should be no issue. And, essentially being guppies, they're cute and fun to watch...and the fact that they are relatively small is perfect for this tank.

And of course, being a fish geek, I couldn't stop at just one of the fishes on my short list, and things seem to happen in multiples in this hobby.

Lo and behold, I sourced another one of my personal "holy grail" fishes, the butt-ugly, but undeniably cool Krytolebias marmoratus from Punta Maracayo, Puerto Rico! It's common name...wait for it: "The Mangrove Killifish!"


Doesn't the common name pretty much tell you all you need to know? Yeah, it does...A kilie found in the freaking mangrove habitat! Okay, so it won't win any awards for beauty, but damn, how cool is that! Add to the equation that it's known to be a bit of a cantankerous son of a b--- on occasion, and you've got the makings of a truly great fish! 

This is one of the most fascinating of the (formerly) Rivulus genus.

Interestingly, the species consists mostly of hermaphrodites which are known to reproduce by self fertilization- a real "time saver", I suppose! An individual hermaphrodite Mangrove Killie fertilizes itself when an egg and sperm that it has produced via an internal organ unite inside the fish’s body. This process has apparently been going on for several hundred thousand years, and the species has been undeniably successful!

Another interesting attribute of this fish is that it can spend up to two months OUT OF THE WATER- when it jumps into hollowed out logs and such if its habitats begin to dry up. During this time, it breathes through its skin, and waste is also exported this way. Its gills actually alter their structure during these periods..And when it returns to the water, these "modifications" reverse.

Super cool.

(image by Cardet co6cs- used under CC BY-SA 3.0

Of course, there is one wild card here:

The fish is a champion jumper, which means the likelihood of me seeing one or more catch air and carpet surf from time to time during their tenure in my open-top mangrove tank is...well, pretty damn high. The good news is that they have the aforementioned highly adapted survival skills that will enable them to survive before I can toss 'em back in the tank.

I know that a lot of killie keepers might not be happy with me for even thinking of keeping the fish in such a tank, and I know that a ration of shit is headed my way in the form of DMs and Facebook call-outs, but I'm prepared to make recovery efforts as needed....And ultimately, I'll move 'em to a dedicated closed-top tank if it becomes too common an occurrence. 

That being said, I'm totally into this fish. I've kept a bunch of the more "attractive Rivulus" before, so this uniquely monochromatic species is going to be a lot of fun...if it stays in the aquarium, that is. 

So, there's gonna be a few changes around the old "mangal" , as they say, with a strange but somehow workable combination of different brackish water species making their debut.

Thought you might want to know where this tank is at...Looking forward to some more information unlocks on these species as we play with them in this aquarium. And of course, more pics!

SO, thanks for the little nudge!

Stay persistent. Stay bold. Stay dedicated. Stay curious...

And Stay Wet.


Scott Fellman

Tannin Aquatics 




Scott Fellman
Scott Fellman


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