The Route of the Cardinal Tetra (Paracheirodon axelrodi)

 The route of the Cardinal Tetra 

Photo 1

One of the aquarium fish with more pages held in the books of hobbyists than Discus and Angelfish combined is the Cardinal tetra. More precisely, Paracheirodon axelrodi.

These characids we could consider as the most popular tetras in the ornamental fish hobby, their distinctive color contrast and beauty makes them unique and although there are several similar tetras such as the Paracheirodon inessi (previously in the genus Hyphessobrycon) or P. simulans, they do not possess the elegance of that of the King of the tetras.

Such is the importance of this characid, whole families livelihoods depend on their capture consistently surpassing other species. I have seen what the natives call “viveiros” along rivers with thousands of these nets which separate fish by size, as well as the typical plastic boxes containing hundreds of fish each occupying entire boats.

In the collection centers where all the fish go to undergo quarantine before being exported, Cardinal tetras are always those who take up more square feet in their pools and have a section for themselves! Surely this is the most commonly extracted fish from Amazonas.

 

Biology of the Cardinal Tetra

Photo 2Cardinal tetras are a fish more commonly identified with very acidic, soft, black water. This tetra belonging to the class Actinopterygii, Order Characiformes and Characidae family, is located in the southern Amazon basin from Venezuela to Colombia, also in the Rio Negro basin in Brazil. Its colouration is globally recognized and is divided along the fish in three different bands with a first deep red at the bottom of the body from below the eye to all the way to the caudal penduncle that occupies half of the fish longitudinally. Crossing parallel to its red stripe and stretching from the eye and often right to the birth of the adipose fin is a blue or green iridescent band (depending on the angle of light), and the final strip shows a grey/brown base colour dorsally with some occasional iridescence to match.

It is a gregarious fish that nature would always see travelling in a minimum group size of about seven or eight individuals which tend to often carry a darker colouration when set against their common background, a bed of leaves which highlights their intense colors. It is a peaceful species, particularly with regard to interspecies dynamics, I have seen many tetras of different species among groups of cardinals with no signs of discomfort. For example, Cava Sp, Nannostomus sp (several species), Hemigrammus sp, Hyphessobrycon heterorhabdus among others, forming shoals.

Males are smaller than females and more slender, females have a more robust and more rounded belly.

One important thing that I saw in the biotope is that at night when they sleep, they do so hidden behind a leaf or branch but quite contrastingly to their daytime behaviour they are always alone, then when the daylight comes back, they can be found once again together in shoals. Also their colors at night time are “off” looking faded, pale but then with the arrival of the day are regained in strength of coloration.

As for food, it is a fish which is typically omnivorous and opportunistic but their main food items consist of zoobenthos including small crustaceans which inhabit the substrate and aquatic annelids such as larvae of Chironomidae which are also found among the substratum, the leaves and branches.

The story of the Cardinal tetra:

Few aquarium fish have a story so very particular as the Cardinal Tetra, I could tell the story myself, but is was once written in detail by Heiko Bleher and even includes the history of the Neon tetra (Paracheirodon innesi). Being personally acquainted, I would like to tell the story as it was written by him which I have been kindly authorised to do:

“In 1934, the French August Rabaut, having been hunting alligators and butterflies in the Amazon jungle near the Brazilian town of Tabatinga, discovered and collected a small fish whose color resembled that of the beautiful iridescent Morpho butterflies. The back of his body was bright red like lipstick and the overall effect of the colors made one think of the neon light. Rabaut brought back to France a few of these living beings – one of the most remarkable in the history of aquarium events.

The Neon tetra

In Paris, the small Neons were a sensation and soon were in books. They passed from the hands of JS Neel Company Lepant to Mr. Griem, Aquarium Hamburg in Germany, who at the time was entertaining a guest from the US, Fred Cochu. Fred managed to steal six live specimens and brought them back to America on the 144th (and last) flight of the aircraft Hindenburg (its next flight ended in disaster in Lakehurst, when the Hindenburg exploded and most passengers were killed) . Although Fred reached his destination without incident, only one of his neons survived the trip. It was given the name “Lucky Lindy”. as Charles Lindberg was the first of his kind to cross the Atlantic.
The dead Neons were given to the internationally famous editor Williams T. Innes in Philadelphia, who in turn passed some of these fish to ichthyologist George S. Myers, who had studied with the famous Carl Eigenmann who was a recognized authority on fish, amphibians and reptiles. On July 3, 1936, Myers published the original description of this species in the “Proceedings of the Biological Society of Washington” under the name of Hyphessobrycon innesi, this way honoring a man who may not have had anything to do with the discovery of the fish, but nevertheless deserves our thanks for his services to the aquarium hobby.
At that time, Rabaut had realized that he had stumbled upon something valuable, and in 1936 returned to Brazil to collect neon tetras commercially. He took the first shipment of 4,000 specimens to New York. Innes Williams had recommended Fred Cochu of Paramount Aquarium and both were waiting for Rabauts arrival. This represented a sensational story for Innes magazine and Cochu wanted the neons. He offered $ 4,000 for the fish – an incredibly high sum for the time. The first neons went on sale in the market at $ 10 each, and all were sold. Fred It took a week to get the money together to pay Rabaut on time, and then made a contract with him to collect these fish for the aquarium Paramount. Fred thought that only Rabaut knew the original source of the neons and was not willing to reveal it. But in Germany a “gold rush” of neons was underway, and a team of Aquarium Hamburg, including Hans W. Pietch and Praetorius, was already underway at Benjamin Constant (Tabatinga). Rabaut was already back to New York with the second large shipment of neon when he stopped in the capital of Amazonas for the night. The Germans boat was anchor near Rabaut, they spotted the bottles with neon and threw all the fish overboard. Thus, Aquarium Hamburg got the advantage in the race of neon collection. Rabaut had to go back and capture it all again ….
At this point, Innes and Myers cited the source of the neon tetra as “probably near Iquitos,” while others said it was Tabatinga. However, it is now known that the species has special requirements of a biotope. The species is found mainly in Peru in the so-called “quebradas”, small creeks of clear water with a significant blackwater component, wherein the pH ranges from 5 to 6 and temperature from 24 to 29 ° C and total hardness is less than 1 dGH. Its natural distribution is limited to the upper Amazon, the lower to middle Uyacali near Iquitos (Rio Nanay, Rio Mannequin) lower and close to Sao Paulo de Olivenca, Brazil, is also known to be in the Putumayo River and elsewhere.

Cardinal tetra

As the neon tetra was a sensation before the Second World War, in the same way the Cardinal was a novelty in the post-war. Around 1950 it was rumored that a new “Neon” had been discovered in the Amazon basin. Harald Sioli, the pioneer of research in limnology of Amazonas, was the first white man to see the fish, while working on the upper Rio Negro in September 1952, but thought he was dealing with the neon tetra. An airline pilot on Panair do Brasil, Captain Malm, who was also a fan of fish, heard about this and around the year 1952 commissioned some Indians who harvested the first living cardinals.
These were a hit with aquarists in Sao Paulo, so the captain Malm organised subsequent collections of “cardinais” (as the call Brazilians today) whenever he had a chance during his adventurous DC-3 flights over the jungle. By the end of 1953, Amanda Bleher saw some of these “red neon” (as they are known in Germany) in Sao Paulo during her intrepid expedition to South America in search of Discus, and bought some specimens, the first Cardinals to be exported . The flight to Germany in March 1954 lasted 37 hours and unfortunately all the fish were dead on arrival. Others, she later transported in special fish cans, died in a tragic bus accident that eliminated her entire collection of new fish, plants, insects and reptiles. This gem of a fish apparently first became noticed by the people of the United States in 1955, when the new species was simultaneously and independently described by prominent American ichthyologists in two different publications – by LP Schultz of the Smithsonian Institute, and on the other, by George S. Myers and Stanley Weitzman at Stanford University. This meant that two scientific names were published, Cheirodon axelrodi and Hyphessobrycon cardinalis, reflecting the views of the two groups of authors regarding its generic placement. This led to an unfortunate debate that eventually went in favor of Schultz, and thus Cardinal (and neon) was named in honor of a man who had nothing to do with its discovery. The newly discovered cardinal was even more colorful than its cousin the neon, since the red coloration extended over almost the entire length of the lower half of its body. But commercial collections and export did not begin until late 50s. This happened when the Austrian animal collector Hans Willy Schwatrz (who had recently helped Walt Disney with his film about the Black Panther) realized the great potential of this fish, to sell the first 10,000 cardinals for $5 a piece to a Chinese named Chung who lived in Georgetown, Guyana in 1959. In 10 years, Cardinals became the most popular aquarium fish, and nowadays, a little over 50 years after its discovery, remains the number one, most aquarium fish sold worldwide”.

Biotope: It is not always black water.

Biotope: It is not always black water.

I’ve been lucky enough to appreciate this characid in two types of biotopes with many features in common but distinct between them.

It is normal to associate the Cardinal Tetra with black water and although its main biotope, they are also found in “Morichales” within the Amazon Basin and Orinoco. These are small streams and lakes that run through the jungle with water which is crystal clear, some with strong current, while others with little current if any. These “morichales” named after the Moriche Palm (Mauritia flexuosa) that grows in damp areas such as swamps and spends part of the year submerged or semi-submerged. Even in the dry period from November to March this palm is usually always wet or very damp.

In both biotopes I have seen, the water parameters are similar and here’s these four photographs of places where we fished “Tetra Cardinals” (including P. simulans):

 

RIO NEGRO BRAZIL: igarapé Demini in 2007

Rio in black igarapé Demini (Brazil): pH 5.20;  Conductivity 6us;  Water temperature 29,5C °;  Extremely black water.
Rio Negro, igarapé Demini (Brazil): pH 5.20; Conductivity 6us; Water temperature 29,5C °; Extremely black water.

 

VENEZUELA, Orinoco in Morichal.

Morichal in Venezuela Orinoco clear water (Venezuela): pH 4.35;  Water temperature at noon 26,1C °;  Conductivity 6us;  Entirely clear water.  Here I could shoot from several other fish.
Morichal in Venezuela Orinoco clear water (Venezuela): pH 4.35; Water temperature at noon 26,1C °; Conductivity 6us; Entirely clear water. Here I could shoot several other fish.

 

VENEZUELA: Atabapo River

Atabapo River flooded forest (Venezuela): pH 3.48;  Conductivity 6us.  ;  Water temperature at noon 29,7C °.  Extremely acidic and black water.
Atabapo River flooded forest (Venezuela): pH 3.48; Conductivity 6us. ; Water temperature at noon 29,7C °. Extremely acidic and black water.

 

COLOMBIA: Caño Anapo.

Caño "ANAP" a small tributary of the Orinoco (Colombia): 3.70 PH black water.  5us conductivity.
Caño “ANAP” a small tributary of the Orinoco (Colombia): 3.70 PH black water. 5us conductivity.

Fishing for Cardinals:

“Every year, more than 20 million cardinals are captured during the official and regulated collection season (August to April) representing over 50% of exports of fish from Brazil.” (Heiko Bleher).

These words from Heiko tell us how important this aquarium fish is for those indigenous families in the collection areas. It really is the case because most Cardinal Tetra fishermen prioritize this species instead of catching other fish required by the market such as Pistrellas sp. and various other tetras sharing the biotope including Hemigrammus bleheri (and the other two species Petitella georgiae and Hemigrammus rhodostomus). I have also seen inside boxes containing cardinals, stowaway fish such as Crenicara sp. which were unfortunately among the cardinals when captured.

Fishing Methods:

A camp is usually situated in the middle of the jungle in an open space to allow for the arrival of small vessels such as Voadeiras (Brazil) or Flying (Venezuela and Colombia) as well as canoes.

Classic camp ornamental fish boxes stacked note which will then be loaded onto ships.
Classic camp ornamental fish boxes stacked note which will then be loaded onto ships.

 

This place is close to several collection points which are usually small streams (igarapé in Brazil or “Cañito” in Venezuela or Colombia) where the Cardinals are. These camps called “Viveiros” are where the cardinals are placed in submerged net “cages” within the river which allows a constant circulation of fresh water. The fish remain here for several days to until the required quantity is collected and to warrant bringing a large boat with fish crates etc.

Here we see the "viveiro" armed on the coast of the camps.
Here we see the “viveiro” armed on the coast of the camps.

 

The cardinals are captured by natives with a particular net called a “napa” consisting of an oval and large hoop with a very particular “T” grip handle to allow it to be maneuvered with one hand whilst the other hand containing an oar scares the shoal towards the net.

The special network capture Cardinals
The special network capture Cardinals

 

Usually the fish are in large schools but among them there are different interspersed tetras which are also captured (Belgian tetra, Pistrellas sp., Several different Nannostomus sp. In Orinoco Atabapo). On the Rio Negro they were among Hatchet fish (Carnegiella marthae) Nannostomus sp. (various species) and some small cichlids such as Crenicara sp, Apistogramma or dwarf Crenicichla.

Siempre el viaje de pesca de cardenales comienza bien temprano a la mañana ya que los cardúmenes se encuentran unidos, ya por la noche los peces duermen separados y escondidos como también pierden el color y es difícil poder distinguirlos de los otros tetras.

Carnegiella marthae in one of the boxes interspersed with Cardinals.  Demini River tributary of the Black River, Brazil.
Carnegiella marthae in one of the boxes interspersed with Cardinals. Demini River tributary of the Black River, Brazil.

Once collected, the boxes are checked several times along the river checking for tetras or small fish that are not cardinals, most are thrown into the river leaving them free but some other species required by the aquarium trade are placed apart (Crenicara sp., Hatchet fish (Gasteropelecus) & different tetras) which together with the cardinals are then loaded into the classic transport boxes to bring them to the collectors on the barges. Sometimes the Piabieros own camp are responsible for separating the Cardinals by size using a sieve of wood and sometimes a net, either one way or another Cardinals are separated by their sizes with larger specimens being called “jumbo”.

Also from the time they are placed in crates, carriers use a medicine to prevent stress-related illnesses which acts as a tranquilizer for fish. Fishermen always have fish as they charge for each fish, receiving a small sum of money every 100 cardinals, equivalent to US $ 2 each about 100 fish.

At the accumulator station the fish remain in quarantine for about 4 weeks and these businesses will be responsible for transport of the fish by air to the capitals of the world.

Barcelos barge carrying ornamental fish, these were filled with Tetras Cardinals
Barcelos barge carrying ornamental fish, these were filled with Tetras Cardinals

 

The Exporters:

This time we visited “Turkys” one of the most important collectors in Manaus, capital of the Brazilian Amazon. This place is responsible for quarantine which is held here in garden pools exclusively used for Cardinals,  since the main cash income is through this fish. White tiled pools are also used for Discus (Symphysodon) and others such as Angelfish (Pterophyllum), various Catfish and Piranha.

 

I cardinals who were already captured are shipped in these boxes with my little water thus preventing overflow for any wrong movement of the vessel, with the motion of the barge oxygenated water is kept, plus the wives or children of fishermen are doing them water changes along the way.
Cardinals which were already captured are shipped in these boxes with a little water thus preventing overflow due to movement of the vessel. Oxygenation is maintained by the motion of the barge and the wives or children of fishermen are replace water frequently along the way.

As well as the motion of the boat helping to increase oxygenation, the wives or children of fishermen do small water changes using the river was on the way and also remove any dead or dying fish.

Details of these boxes full of Cardinals
Details of these boxes full of Cardinals
We could see that after several checks by piabeiros (fishermen on the river) is still a stowaway among the cardinals here for a Crenicara sp.
We could see that after several checks by piabeiros (fishermen on the river) is still a stowaway among the cardinals here for a Crenicara sp.
The dozens of boxes stacked with cardinals inside.
The dozens of boxes stacked with cardinals inside.
Right on the water change, arriving at the port of Manaus before being transported to the gatherer for quarantine.
Right on the water change, arriving at the port of Manaus before being transported to the accumulator for quarantine.
Once in the gatherer are placed in huge wading pools (in this case) or pools on the floor as we saw in Inírida, Colombia.
Once in the farm, the fish are placed in huge wading pools (in this case) or pools on the floor as we saw in Inírida, Colombia.
Another view of these pools filled canvas Cardinals.  Note that they are protected indoors avoiding sudden changes in temperature and PH (sun and rain)
Another view of these pools filled canvas Cardinals. Note that they are protected indoors avoiding sudden changes in temperature and PH (sun and rain)
View of the "office" Turkys, work outdoors.  Some boxes with more delicate fish behind us.  From left to right: William, author, Maria and Enrique.
View of the “office” Turkys, work outdoors. Some boxes with more delicate fish behind us. From left to right: William, author, Maria and Enrique.

 

A port coupler Inírida, called "Los Pozos".  Detail of the concentration of cardinals.
One place in Inírida, called “Los Pozos”. Detail of the concentration of cardinals.

 

In Puerto Inirida, Colombia, blackwater rivers are used to create pools, they are used by diverting a small trickle of water from the river. Pools contain different batches of cardinals separated by size e.g. “Jumbo”.

Gatherer "Los Pozos" Here we can see more of the craft pools on the floor using a small stream of water from the River.
Gatherer “Los Pozos” Here we can see more of the craft pools on the floor using a small stream of water from the River.

Once the Cardinals are recollected they are held for a few days already acclimated and fed with artificial food. They are recaptured and packaged for transport to the nearest city of connection to the rest of the world, e.g. fish stationed at Puerto Inírida are taken to Bogota or those from Manaus are taken to Sao Paulo or Rio, as well as from Puerto Ayacucho to Caracas.

Main courtyard where oxygen is bagged and placed in styrofoam coolers.  Note the large tank of oxygen lying on the ground to use it more comfortably, it is customary to sit on the tube as he charged oxygen (why is worn by sitting).
Main courtyard where oxygen is bagged and placed in styrofoam coolers. Note the large tank of oxygen lying on the ground to use it more comfortably, it is customary to sit on the tube as he charged oxygen (why is worn by sitting).
Jaison "sitting" on the tube of oxygen for oxygen transport bags of fish.
Jaison “sitting” on the tube of oxygen for oxygen transport bags of fish.

 

Countless species are transferred from the Amazon to the cities, usually the Cardinal Tetra is the higher output and much of the coupler is dedicated to this wonderful fish.
Countless species are transferred from the Amazon to the cities, usually the Cardinal Tetra is the higher output and much of the premises is dedicated to this wonderful fish.

 

Boxes ready to place the fish and shipped by air to major cities.
Boxes ready to place the fish and shipped by air to major cities.

 

Finally, I would add that the way to pack them and transport them is quite safe but the way out of their biotope until our aquariums is very long and unfortunately there are many casualties. Although once acclimatized this beautiful tetra might become a very hardy fish and if we can provide water according to its needs will show its best, there is an important obligation of the fishkeeper to always think of their journey and practice correct acclimatization. Without this acclimatization their survival in the aquarium is frequently affected.

 

Today these fish are reproduced on a large scale, mainly in Asia but most which are sold to supply the large aquarium trade continue to come from the (endless?) Amazon.

__
Acknowledgements:

Alfredo for accompanying me on expeditions, to my family that endures my obsession with fish, Perico covering me on trips.

References: Bleher’s Discus Volume 1

Marcelo Fernandez

Jorge Marcelo Fernandez is the owner of Wild Fish Aquarium based in Argentina. Through his website, he documents his travels to investigate the biotopes of the fish he loves most.

Marcelo Fernandez

Jorge Marcelo Fernandez is the owner of Wild Fish Aquarium based in Argentina. Through his website, he documents his travels to investigate the biotopes of the fish he loves most.

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