The Guardian of The Spring

Have you ever had that ONE fish which just sort of occupies a place in your heart and mind- a fish that-for whatever reason- bit you and never let go? I think that every serious aquarist has such a fish..

Here's mine...

As a lover of the use of leaf-litter in our botanical-style aquariums, I am fascinated not only by this unique ecological niche, but by the organisms which inhabit it. We've 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!

And 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! 

And it all starts with its intriguing name...

The Latin root of the genus Crenuchus means "Guardian of The Spring"- a really cool 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."


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" fishes, which tend to lie in wait near the substrate, 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!

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 collect, hold onto, and enjoy as it evolves and grows. As the fish matures, 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. Individuals spend a lot of their time sheltered under dead leaves, branches, roots, and aquatic plants. They feed during the daylight hours, and are mid-water feeders, consuming particulate organic matter, such as aquatic invertebrates, insects, flowers, and fruits- the cool food items from outside of the aquatic environment that form what ecologists call allochthonous input- materials abundant in the botanical habitats which we love to model our aquariums after.

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

Are you interested yet?

I first fell for this fish as a kid, when I saw a cool pic of it in a well-worn copy of William T. Innes' classic book, Exotic Aquarium Fishes.

I was hooked from the start, especially when reading about the romantic etymology of the name! 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 to find this fish again, and I jumped at the chance, and I didn't regret it one bit! The Sialfin is one of the most engaging and unique fishes I've ver 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!

And all though they are a bit solitary in nature, I've found that they've done really well in groups, sometimes forming loose aggregations within the confines of the aquarium, hovering over the leaf/botanical bed, waiting for food. It reminds me of the behavior I've observed of some of my favorite reef fishes, the Pseudochromids- 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. 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. If you have other, monroe 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.

So, imagine how excited I was when I heard that Mike Tuccinardi was able to secure a number of these unique characins for our Tannin Live! collection! This is one of those fishes that you really sort of "have to trust us" about...Once you keep it, you'll just sort of "get" it! They're one of the most perfect fishes for the botanical-style, blackwater aquarium, and will fit right in to a well-thought-out community aquarium of smaller fishes, like Tetras, dwarf cichlids, and catfishes- and perhaps one of the only characins which we can say has a real "personality!"

If you're looking for that "it" fish that will really make your botanical-style aquarium "pop"- give some real consideration to this wonderful fish! 

Trust me, having the "Guardian of The Spring" in your aquarium is worth the wait!

Stay relentless. Stay fascinated. Stay diligent. Stay patient. Stay excited! 

And Stay Wet.


Scott Fellman

Tannin Aquatics 

Scott Fellman
Scott Fellman


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