February 16, 2021

The continuing saga of my search for a blackwater livebearer: Episode III: A new Chance

Not a long time ago, in a column right here, I shared with you my desire to find a livebearing fish species which is commonly found in a blackwater habitat. It's been an interesting saga, filled with twist and turns, punctuated by my lack of recent direct, personal experience with wild livebearers, yet, buoyed by findings from research papers and ideas from fellow hobbyists.

If you recall, in our last review of this topic, we did stumble upon a few interesting candidates.

Most of them, such as the genus Fluviphylax, which, as I said before, "contains five described species, not one of which anyone who is not a native fisherman, lifetime member of the American Livebearer Association, or doesn't have the letters "PhD" after his/her name, has even heard of- let alone seen! These are rather interesting fishes, distinguished by really large (relative to their body size), almost "creepy-looking" eyes, the absence of a gonopodium in males, and the usual complete lack of color seemingly common to pretty much every obscure fish in the world..."

Shit, that felt good to quote my own article! And I think I was accurate! 😎

(A genuine candidate. Fluviphylax shows it's true "colors"-or lack thereof. Image by Clinton and Charles Robertson, used under CC BY 2.)

I'll wager that this fish will never be found anywhere in the hobby, unless it's by total accident- the product of "by-catch" by commercial fishers looking for something a hell of a lot more viable in the trade!

This species looks an awful lot like a killifish to me!. And, they're apparently endemic to the Amazon and Orinoco region, including habitats like lakes, swamps, and "floating meadows", any and all of which could be filled with tannin-stained blackwater, right? As I pointed out before, Fluviphylax obscurum, which drew me in from the start- is listed as having its native range being the "Upper Rio Negro basin!"

That's intriguing...

But the trail went cold for a bit, as I moved on to other stuff...

BACK IN THE HUNT.

Fast forward to 2021.

I recently received my long-awaited copy of "Fishes of the Orinoco in The Wild" by our friend, Ivan Mikolji (NOTE TO READERS: GET THIS BOOK! PERIOD. JUST GET IT- you'll thank me.), and was pleasantly surprised to see a section with some members of the Family Pociliidae!

More clues! And, on page 278 in this must-have book, what to my amazed eyes did I see but our good friend, Poecilia cf. reticulata, AKA, the Guppy? Well, specifically, a variety known as the "Orange Line Guppy. One that I have seen before! This was huge!

And, sure enough, Ivan relates his enchanting first encounter with these little beauties, in a blackwater habitat- the Rio Morichal Lago in his Native Venezuela!

He described that they tend to stay in schools in the most shallow parts of the river, and that they, "do not venture more than 1.5 meters offshore where the water gets really dark and larger fish live."

(Rio Morichal Lago, Estado Monagas, Venezuela. Image by Cesar Perez)

That was all I needed to hear, but the accompanying photo really let this sink in: A small group of these fishes in tinted waters, with a gently sloping sandy bottom, covered in decaying leaves, twigs, and botanical materials! Ivan indicates that the pH in this habitat ranges from 4 to around 5.5- undisputedly acidic; conditions which we seldom seem to associate with livebearing fishes!

They're beautiful little fish, with the males possessing an unusual pinkish-orange horizontal line across the body, with a small almost black marking at the caudal peduncle. They also possess a smaller, less distinct black spot behind the pectoral fins. The females are "generic livebearer silver-grey."

I've also seen these fishes on sale from various breeders listed as "Campona Guppies" or "El Salto Guppies", collected near Ciudad Bolivar, 50km east of El Tigre in Venezuela, in the same Rio Morichal complex Ivan refers to in his book. Curiously, despite the common moniker 'Guppy", most of the hobby listings I've seen indicate that they are Poecilia wingei ‘Campona’ (you know, like "Endler's Livebearers), so there is much taxonomic confusion, to say the least!

All that being said, these are very intriguing fishes to me. Whatever the hell they're called.

Now, what makes this particular obsession/search of mine so alluring and simultaneously frustrating is that many of the livebearers encountered in the trade -and often in the wild- were introduced from other areas. Because of their adaptable nature, you're likely to find them in a huge range of habitats, from brackish water (yay!) to soft, acidic water. However, it seems to me that most of the species come from more coastal locales, and the water might be "colored" through silt and mud, as opposed to the "blackwater" that geeks like me are fascinated with.

And of course, inevitably, after all of this tedious research, I've once again found that there are, as we know- tons of cool, often obscure livebearers that we can keep in brackish water "estuary"- themed tanks!

Poecilia picta, AKA the "Swamp Guppy"- an unsung brackish water beauty!)

Back to those "Orange Line Guppies."

In almost every research paper I was able to find which mentioned this species, it was referred to essentially as the "Guppy"..and of course, it is..well, sort of. Again, the taxonomy is a mess, but the range seems to be somewhat similar. Okay, that's probably a bit of a stretch on my part, but superficially, it appears to be largely the same as any other Poecilia reticulata...

But, here's the thing: Every reference to this particular variety/population indicates it tends to be found in blackwater habitats only. There is no mention of "brackish" occurrences for this population. It seems pretty much a given that it's a blackwater-occurring population.

The underwater ecology includes essentially a "greatest hits" version of the botanical materials we love: Decomposing leaves, twigs, tree roots, and plant parts (including palm fronds), over a bed of silty, loosely aggregated sand. Our kind of place! The water is clear but tinted a golden brown, with an average temperature of around 26C/76F, and a pH ranging from 4-5.5, with as we mentioned previously. Conductivity was around 15 -30 μs / cm.

Yeah, blackwater, by any stretch of the imagination!

Here's a little passage from a paper I found on the "Campona Guppy" in it's natural habitat by researcher F.N. Poeser, an example of the kind of gems you can find online if you dig hard enough:

"The river was about 150 cm deep with the bottom clearly visible, about 180 to 300 cm wide and no submerged vegetation was observed, the observation area was a stretch of about 40 meters. There were trees and some dense vegetation at several positions at the bank. The Campoma guppy was syntopic with the following species: Catoprion spec., Crenicichla spec., Cichlasoma spec., Rivulus spec., Ampullaria spec., and some unidentified crustaceans.

The observed subpopulations, i.e., groups of about twenty adults of both sexes and about 20 sub-adult and juvenile fishes, occupied positions near the river banks. At different locations of this stream we observed other groups with approximately 60 adults, with about 50 subadults and juvenile fishes. The females were continuously grazing the loamy ground, swimming in groups of 6 to 10 fishes. In this stable environment, subgroups are formed consisting only of females."

Now, think about it in fish geek terms for a sec...

The researcher describes the whole setup nicely...Even the other fishes that these guys are found with! And their behavior, too! Interestingly, in the wild, these fishes tend to aggregate in sizable groups. Imagine the interest a large display tank with a nice group of these fishes could create! Sure, it's not perfect for controlled breeding, but you cold have a nice, stable population of some really cool fishes in a system which replicates many aspects of it's natural habitat!

At the end of the day, I'm feeling not only intrigued- but exhilarated to have found at least one livebearer that's semi-regularly available in the hobby, which, by every indication, seems to come from the type of habitats which fascinate us blackwater enthusiasts!

And it just happens to be nice-looking, too.

As I stated earlier in my epic search, "I don't care if the fish is grey, chromatically "uninspired"...or just plain dull! I just think it would be cool to find one that could be "biologically appropriate" for one of our blackwater, botanical-style tanks!"

Damn, I never tire of quoting myself! 😆