Fish hooks man: An homage to "The God of Running Waters..."

There are numerous approaches to utilizing botanicals in our aquariums, ranging from the purely aesthetic idea of "tossing in a few leaves and seed pods", to a full-blown biotope-inspired aquarium, painstakingly thought-out to recreate the function and form of a specific habitat.

Of course, we've talked a lot about creating aquariums to replicate specific's kind of what we do here, right? Super rewarding. Yet, it's even more fascinating and rewarding to design an aquarium around a specific fish sometimes.

Especially when it's one that you have coveted for so long, right?

I'll share with you one of my personal "Holy Grail" I've no doubt discussed many times before here yet one that keeps me obsessed. Being a fish geek, I know that this is something you can relate to well:

We've all had that ONE fish which just sort of occupies a place in our hearts and minds- a fish that-for whatever reason- bites you and never lets go, right? I think that every serious aquarist has at least one such a fish..

Here's mine...

Of course, it's also about the habitat which this fish lives in that's kept me under its spell for so long...

As a lover of leaf-litter in our natural, botanical-style aquariums, I am fascinated not only by this unique ecological niche, but by the organisms which inhabit it. I've went on and on and spoken at length about many of the microorganisms, fungi, insects, and crustaceans which add to the diversity of this environment. And of course, we've looked at some of the fishes which live there, too! Perhaps not enough, actually...

One of my all-time favorite fishes- and my absolute favorite characin is none other than the amazing "Sailfin Tetra", Crenuchus spilurus!  This is a truly awesome fish- not only is it attractive and morphologically cool-looking, it has a great demeanor and behaviors which separate it from almost every other characin out there! 

It's almost "cichlid-like" in behavior: Intelligent, interactive, and endearing. It has social behaviors which will entertain and fascinate those who are fortunate enough to keep it.

Now, I admit, it's definitely NOT the most colorful characin on the planet. But there is more than this fish than meets the eye.

It all starts with its most intriguing name...

The Latin root of the genus Crenuchus means "Guardian of The Spring"- a really cool, even romantic-sounding name which evokes imagery-and questions! Does it mean the "protector" of a body of water, or some honorary homage to everyone's favorite season? Not sure, but you must agree that the name is pretty cool! In greek, it's krenoychos -"The God of running waters."

Yeah. That's the shit. I mean, do Latin names get any cooler than that?

The Crenuchidae (South American Darters) is a really interesting family of fishes, and includes 93 species in 12 genera throughout the Amazon region. Most crenuchids are- well, how do we put it delicately- "chromatically unexciting" ( ie; grey-black-brown) fishes, which tend to lie in wait near the substrate (typically leaf litter or aggregations of branches), feeding on insects and micro invertebrates. And the genus Crenuchus consists of just one species, our pal Crenuchus spilurus, a fish which shares habits and a body shape that are more commonly associated with Cyprinids and cichlids!

That's just weird.

Now, the relatively subdued coloration serves a purpose, of course. These fishes live among leaf litter, root tangles, and botanical tinted water...which demand (if you don't want to be food for bigger fishes and birds) some ability to camouflage yourself effectively. 

The Sailfin is an exception to the "drab" thing, and it's remarkably attractive for a very "simple" benthic-living fish. Sure, on the surface, it's not the most exciting fish out there, especially when it's a juvenile...but it's a fish that you need to be patient with; a fish to search for, collect, hold onto, and enjoy as it matures and grows. As the fish matures, in true "ugly duckling"🐥  style, it literally "blossoms" into a far more attractive fish.

The males have an extended dorsal and anal fin, and are larger and more colorful than females. Yes, colorful is relative here, but when you see a group- you'll notice the sexual dimorphism right away, even among juveniles.

Individuals spend a lot of their time sheltered under dead leaves, branches, roots, and aquatic plants. They tend to "hover", and don't dart about like your typical Tetra would. In fact, their behavior reminds me of the Dartfishes of the marine aquarium world...They sort of sit and flick their fins, often moving in slow, deliberate motions. Communication? Perhaps.

The Sailfin feeds during the daylight hours, and spends much of its day sheltering under branches, leaves, and root tangles, and is a mid-water feeder, consuming particulate organic matter, such as aquatic invertebrates, insects, bits of flowers, and fruits- the cool food items from outside of the aquatic environment that form what ecologists call allochthonous input- materials from outside of the aquatic habitat, which are abundant in the terrestrial habitats surrounding the aquatic ones which we love to model our aquariums after.

And of course, we can easily model our aquariums after these compelling habitats...

Yeah, we've written about that topic a lot...Recreating the habitats of leaves and other botanical materials which the fish frequent in Nature.  Liek, we talk endlessly about this shit, I know, but...

Hey, do those guys who sell leaves on eBay and such make the effort to discuss this stuff with you?  Oh, yeah... they don't...just sell stuff and don't bother to write (ouch, a DIG! )...yeah...No hate there, lol.

Oh, back now from my rather ugly digression...

And, further distinguishing the Sailfin from other characins is the males' parental care (yeah, you read that correctly!) of it's small (for a characin, that is) clutches of eggs (usually only like a max of 100) and larval stages of the fish- characteristic more commonly associated with cichlids than characins! 

Are you interested yet?

Wait, don't answer that! I'll keep going...

I first fell for this fish as a kid, when I saw a cool pic of it in my dad's well-worn copy of William T. Innes' classic book, Exotic Aquarium Fishes. The book that pretty much assured me from toddler days that I'd be a fish geek. I obsessed over the book before I could even read...

I was hooked from the start with Crenuchus, especially when reading about the romantic etymology of the name!  And it just seemed so "mysterious" and unattainable, even in the 1930's...well, especially back in the 1930's, but it seemed downright exotic! To this day, it's one you just don't see too much of in the hobby. And then, tying it together with my love of those leaf-litter-strewn habitats, it was a combo which I couldn't resist!

I never got this fish out of my system, and it took me like 30-plus years of being a fish geek to find this fish in real life. And, you know that I jumped at the chance..It was so worth the wait! The Sailfin is one of the most engaging and unique fishes I've ever had the pleasure of keeping!

Oh, and they are known to "vocalize', producing an audible "clicking" sort of sound that you can hear outside the aquarium...A very interesting phenomenon! Another interesting tidbit of knowledge about this fish" They possess an organ on the top of their head, which according to Gery, is "comprised of rod-shaped cells, encircled by a net of capillary vessels." What's it's purpose? No one is sure.

More mystery. More romance. 


Although they are a bit solitary in nature, I've found that they've do really well in groups, sometimes forming loose aggregations within the confines of the aquarium, hovering over the leaf/botanical bed, waiting for food. And they have a sort of "social order" that only they seem to understand, but it's very evident. A fascinating set of activities which makes them even more interesting-and endearing!

Sailfins might be a bit shy initially upon introduction to the aquarium, as these fishes are cautious, rather "sedentary" characins, and don't swim quite as actively as other characins. Like, no "Cardinal Tetra-style" shoaling behavior here. Getting them to feed regularly in the aquarium- while not difficult- may be a bit of a process, as they are cautious fish, and tend to not stray too far from the botanical cover. 

Think of all of the unique ways we could replicate parts of the habitats which they inhabit. 

If you have other, more active Tetras and other fishes in the aquarium, they'll be a bit more tentative at first. However, these are decent-sized fishes that will eventually overcome their initial shyness, and move confidently- if not slowly-throughout the aquarium. Though they tend to never stray too far from the protection of roots, wood, or leaves.

My kind of fish!

Once you keep this fish, I'm confident that you'll just sort of "get" it! If you just look at the fish, most of the time, it's really easy to simply dismiss it as "grey and boring..."

It's not.

IMHO, they're one of the most perfect fishes for the botanical-style, blackwater aquarium, especially, if you dedicate a system to their lifestyle and needs. And of course, it will fit right in to a well-thought-out natural, botanical-style community aquarium of smaller fishes, like the less "hyper" Tetras, Apistogramma, and catfishes.  

Again, these fish are so cool when housed correctly that you might want to keep them in a dedicated species aquarium. They're perhaps one of the only characins which we can say has a real individual "personality", which makes them "worthy" of such a committment!

I hope I've encouraged you to search for these amazing fishes...or to consider setting up a dedicated, carefully-configured biotope-inspired aquarium for YOUR "Holy Grail" fish.

Yes, my photos suck. And yes, I am geeked out about this fish. And, need to try them. Build an entire aquarium around them.

And yes, if you do, I'll hit you up for better pics! 😍

If you're looking for that "it" fish that will really make your botanical-style aquarium "pop"- adding a real presence and interest to the habitat you've created- give some real consideration to this wonderful fish- if you can find it! 

Trust me, having the "Guardian of The Spring" in your aquarium is worth the wait! Your botanical-style aquarium needs this fish! It's that cool.

Of course, it's one of many amazing fishes swimming in the tropical waters of the world; one which you as a hobbyist could dedicate and entire setup to, and never get bored or even remotely tired of...really. 

Yes, we all have that one fish. It's what keeps us passionate about the hobby; keeps us going. Keeps us dreaming, striving, searching.

Find yours. 

Embrace it. Love it. Share your work.

Stay persistent. Stay diligent. Stay resourceful. Stay passionate. Stay relentless...


And Stay Wet.


Scott Fellman

Tannin Aquatics 

Scott Fellman
Scott Fellman


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