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Green Neon Tetras in the Wild

By Ivan Mikolji / 2020

GOOD MORNING

“Good morning Ivan. Did you know that we have the best pineapples here in the Amazon?”

“Good morning Alipio, I did not know that. Let’s hurry before we miss the sunrise.”

With that brief exchange, we head off into the early hours of the morning. It’s 4:30am and still dark, warm and humid as it usually is in the Amazonas State in Venezuela.

As we drive away from Alipio’s house we start to discuss what I want to accomplish with the day.

Alipio, an Amazon- born and river-reared aquarist, is as excited as he always is to go on this new aquatic adventure with me. He’s one of those people fortunate enough to be gifted with great memory, as well as an innate understanding of how nature works. He’s an incredible asset to my explorations, and while he’s with me things get done correctly.

This sultry morning, we are driving north to the indigenous community of Picantonal. While it is not so far away from the town of Puerto Ayacucho, we do still have to take ourselves off-road and a couple of miles deep into the bush.

We are the only car driving along the dark, precarious road, and with the windows down the sweet smell of jungle is always present. At this time of the year the scent is a mixture of wet tobacco, alongside the sap and bark medley of locally chopped wood.

Our first task of the day is to photograph the sunrise from a high spot, to formally record the terrain, and so we decide to climb the Picantonal Western Inselberg.

Inselbergs, which translates to ‘island mountains’ are massive hills or mountain-like granite uplifts,

each made of one rock.

Vellozia tubiflora 3297
Tabebuia orinocensis 6722

INTO THE SANDS

We off-road through a sandy savanna that is covered in Trachypogon grass and over the rocky lajas (pronounced ‘la-has’). These lajas are actually the tips of buried inselbergs that erosion has still yet to uncover. Each of them is bedecked with exotic endemic plants like Vellozia tubiflora and Tabebuia orinocensis.

We get to the edge of the tall inselberg, and retrieving our gear we start to climb until we have a great view of the valley. We sit on the black rough rock, set up the gear and smile; we both know we are privileged, but just being here carries some deep spiritual significance.

We climb down and head to the Picantonal River, at the bottom of the valley some half a mile away.  The Picantonal River is narrow and short, around eight miles long, born right between the east and west Picantonal inselbergs and drains into the Orinoco River. Its water comes out of the ground in a spring filled with Morichal palm trees, Mauritia flexuosa, with a pH below 5.0, KH of less than 20mg/L, a GH of less than 10mg/L, and a temperature around 26 to 28°C. In the deeper pools it even develops a light blue tinge.

Alipio takes the opportunity to repeat himself, reminding me:

“The pineapples from this area of the Amazon are the sweetest. You have to try them”

We divide the stream into four sections. We name the uppermost section the ‘savanna pools’, a little bit lower is the ‘Neon Tetra Pozo’, then the ‘red plants’ section and last, the ‘Picantonal Lagoon’.  A Green Neon biotope in all its glory.

Picantonal rainy period
Picantonal dry period

TURQUOISE IN THE RED

The red plant section is the most interesting habitat for me. It’s a small stretch of the stream about seventy metres long by eight metres at its widest, containing red aquatic plants that look like red hair. This is the only place where we have found these plants — they seem to be endemic to this specific seventy metre spot.

When you look at the plant it looks like Eleocharis but in the dry season when it blooms, its flower seems to be of the Xyris genus, only with a white flower instead of a yellow one. The red plant section is where the river passes over a laja, so there are no tall trees and subsequently no shade, and the water is very shallow at a maximum of 60cm in depth.

In the two ends where there are trees and shade, these plants are green. This is similar to what I observed in Cano Cristales, Colombia where the Macarenia clavigera plants also are red over the sun beaten lajas and green in the shaded areas.

By now the sun is out, beating on us relentlessly over the barren black rocks of the red plant section, and I am sweating and overheated as I put on my aquatic gear. I walk to the middle of the stream and submerge myself into a surreal underwater world. As I lay there soaking up the underwater magnificence, I see blue twinkles of bright turquoise and blue light. They are Green Neon Tetras, Paracheirodon simulans.

Psimulans are delightful freshwater fish that don’t grow as big as their close and more famous relatives, the Cardinal Tetra, Paracheirodon axelrodi, or Neon Tetra, Paracheirodon innesi. Compared to these other members of the genus, Green Neons are more elongated, and their blueish green stripe reaches to the base of their tails, right to the caudal peduncle, which in P. axelrodi and P. innesi ends under the adipose fin.

Another difference is that they don’t seem to school in close alignment as their cousins do. In an aquarium P. simulans seem to be all over the place, each one going wherever it pleases and turning greener than when they are in the wild.

I get out of the water to have some lunch which Alipio has prepared. It consists of a canned spicy tuna that has corn, peas and a side of soda crackers. To drink we have cola which because we don’t have ice is now about 50°C — the perfect coffee substitute. We’re now many hours into our expedition, and Alipio’s mind is still on fruit.

“I wish I had some of that Amazon pineapple. It’s so juicy, it would be the perfect desert. Wait until you try it.”

INTERACTING WITH THE LOCALS

Right next to us, in the wet, soggy, river bank I spot a palustrine orchid (half terrestrial / half aquatic), with a bright purplish pink flower growing out of the aquatic plant mush. I take the time to photograph it from every angle, from the bottom, top sides and even its internal reproductive organs with a macro lens. Then, as I explore the underwater world, I notice that there are other aquatic plants. The one that sticks out the most between the red aquatic plants are the Eriocaulon melanocephalum pipeworts which are fluorescent green and look like tiny, long, crazy haired paint brushes.

All these plants grow strongly attached to the laja granite rocks; there is no gravel or sand in this section. As I lie in the shallow fast flowing water, I notice that there are small groups of Green Neons of up to 15 individuals in different spots of the habitat. They do not have large territories like P. axelrodi, preferring to stay in the same spots, pecking at the periphyton on the plants and on the rocky laja base.

I scratch the laja with my nail and to my amazement the group of Green Neons come and start a feeding frenzy, pecking on the scratched surface while some Red-tailed Tetras, Moenkhausia copei, eat the gunk that floats away in the current. Nothing goes to waste.

Right where the top red plant section ends, the stream turns into a Morichal — an area rich in Moriche palms, Mauritia flexuosa. There the habitat turns dark, and aquatic plants become scarce due to the lack of sunlight. There between the black rocks and the tangles of moriche palm roots is a different world, a dark world where small Hoplias malabaricus wolf fish hide, waiting  for the tetras to get closer and closer until they strike in lightning speed. Here when the light trickles through the palm tree canopy it leaves a clear effect, of a ray of light in the darkness.

I get out of the water to photograph the sunset but Alipio insists we have to hurry to buy some pineapple. We drive across rough ground once more until we reach asphalt road where we see some Piaroa indigenous people selling pineapples next to the road.  I stop the car and Alipio speaks to them in their native language and buys three pineapples from them.  We drive off and Alipio takes his pocketknife, cuts me a piece and stares at me as I taste it.

“Alipio, this tastes like nothing.”

“Really?” and he tastes some himself.

“Ivan, turn around, those guys tricked me, this is the most awful pineapple I have ever tasted in my life!”

We drove back quickly but the guys were gone, they had taken off.

As it was too late to go back for the sunset shoot, we decided to leave it for the next day after we explored the other sections of the river. We drove back with our windows down to Ayacucho consoling ourselves with the sweet smell of the Amazon.

P.S. The semi-aquatic orchid with a bright purplish pink flower was identified by Gustavo A. Romero of the Harvard University Herbaria as Cliestes abdita which until then had not been photographed alive. So, we took the first live pictures of a species without even knowing it.

Cleistes abdita orchid
Cleistes abdita 4861
This article has been published at:
  • Practical Fishkeeping Magazine – July 2020