Piraiba - The Largest Amazon Catfish

In the Amazon River, there are legends of goliath catfish that grow to over 10 feet long and reach nearly 600 pounds. These giants are the catfish that belong to the Brachyplatystoma genus. This genus has 7 of the largest fish in the world, including B. filamentosum. This fish is so large that locals call the juvenile fish (those weighing under 200 pounds) filhote. Once they reach 200 pounds, locals call them Piraiba. The Piraiba is the largest catfish in this genus, and is notorious for its voracious eating and solitary lifestyle habits.

When they’re juveniles, Piraiba are light to dark grey with small spots on their dorsal and lateral sides. As they get older, Piraiba turn dark grey on the top and light grey on the bottom. This coloration aids in camouflaging their massive bodies as they hunt for food 100-130 feet below the surface of the Amazon River.

Piraiba have an appetite to match their massive bodies. Fishermen who’ve caught these massive giants have found small monkeys, birds, cats and even other catfish in the stomachs of these giants. While they don’t hunt for monkeys or birds, Piraibas have no problem scavenging on already deceased animals that have fallen into the Amazon. Some legends even claim that humans have been found in the stomachs of these enormous fish.

Piraibas not only play an important role as scavenger in the Amazon. They also play an important role as food for locals. Fishermen and anglers who hunt these large fish will drop many lines into the Amazon, weighted down by 2-5 pound bait and rocks. Once the line begins to move, experienced fishermen draw the fish into shallow water. At that point, the fishermen have no option but to jump into the water and literally wrestle the Piraibas to ground. For

 inexperienced fishermen this can be a very dangerous sport to learn—the Piraibas are so powerful that they can drown and even drag the wrestling fishermen to the bottom of the Amazon. A successful catch is well worth it though, as a single Piraiba can contain hundreds of pounds of food for locals and export.

Like other catfish, the Piraiba are active at night between midnight and around 6 a.m. Piraiba catfish look for food as deep as 130 feet under the surface of the Amazon River. They will scavenge and also hunt for smaller fish such as Peacock Bass and Piranha. Piraiba don’t worry about the slicing teeth of the Piranha, even though they inhabit the same waters where hundreds of Piranha school. These giants have extremely thick tough leathery skin that resists such attacks. By the time they are 4-5 feet in length, Piraibas can move freely in the deepest Amazon waters without fear of predators.

Piraibas remain solitary until they are ready to mate somewhere between 2-3 years old. When a male is ready to mate, he will find another female Piraiba and swim alongside her until she releases eggs. The male will inseminate hundreds of eggs, and then chase the female from the

 eggs. The male aerates the eggs and keeps the female away, while the female chases predators away from a distance. Within a week, the fry hatch and are fed by the male stirring up detritus on the Amazon floor. The female remains a guardian during this period.

The fry remain at the nest for up to several weeks, adventuring to find small invertebrates and ghost shrimp to eat. They grow fairly quickly, and by 6-8 months they begin to take on sexual distinction and become solitary. This is the most vulnerable period for the young Piraiba—they are mature enough to hunt on their own, but their size makes them very vulnerable to larger fish, giant otters and predatory birds. The Piraiba’s body does offer some protection against such predators that would eat them whole—a characteristic sharp collection of spines on their dorsal that deters predation.

With such a large potential size and healthy appetite, Piraibas are definitely not suitable for most aquarium owners. The best spot to keep a Piraiba is a large local aquarium that can support at least a 2000 gallon tank. These fish can get up to 400 pounds, and with this much body weight, this fish is one of the most expensive to feed and maintain.

Piraiba are one of the most impressive catfish in the world. They dominate the Amazon with their sheer size, and offer fishermen an exciting, challenging catch. They also play a crucial role in scavenging the bottom of the Amazon as the “clean-up crew” of the largest river system on Earth.

Photos copyright: http://www.catfishheaven.net/flavio.html and Wikipedia.org

Piramboia - Evolutionary link between air and water breathers in the Amazon

There’s a very unusual fish in the Amazon that could be the closest ancestor to the first air-breathing life forms on Earth. The South American lungfish, also known as the Piramboia (Lepidosiren paradoxa), is the one obligate air breather that can actually survive outside of water due to its efficient oxygen breathing system. This wonderful fish resembles a mix between a ghost fish and an eel. It has very dark grey to black skin that has a very leathery appearance, tiny eyes like an eel, and its body spreads out in its anterior portion. It can reach over 3 feet long.

The Piramboia seeks slow moving waters and it can usually be seen sitting on the bottom of the shallow ridges around the Amazon River. It rises occasionally to suck in air, only to return to its comfortable nest on the floor of the river. The Piramboia will hunt for insects, snails, berries and shrimp using suction feeding. Unlike other fish in the Amazon, the lungfish can survive on meat and vegetable matter, making it one of the few omnivorous fish.

 The dry season is not a problem for most Piramboia. While other fish struggle with the lack of oxygen in the Amazon River, the Piramboia will burrow into the soft mud at the bottom of the Amazon and wait out the rest of the season. Their metabolism slows and they don’t leave their burrow. The hole can go underground a few inches, and can dry out completely before the rainy season starts again in the Amazon. The Piramboia breathes in air during this dry time, and most survive in their burrows safe from predators. The biggest danger to these novel fish are giant river otters, which know how to dig for them during the dry season.

During the rainy season, the Piramboia will begin mating as the water rises and fresh water flows into the Amazon area. Male and female Piramboia create a burrow-like nest in the muddy bottom. They lay quite a few eggs, and the male guards them voraciously. Upon hatching the fry look like tadpoles and breathe through gill-like structures. The male also develops extra capillaries in his pectoral fins, and will fan the fry to provide more oxygen and remove carbon dioxide. At around 8 weeks the fry develop their lungs and are able to breathe air like their parents.

At first, young lungfish eat mosquito larvae, snails and algae. As they mature, they become adept at catching shrimp and even small fish such as tetras. Whether or not the juvenile lungfish survive to their first dry season is a big factor in whether or not they survive to adulthood. After they have survived one dry season, most of them will grow to full size.

The Piramboia is the only species of fish in the Amazon to possess a true lung structure that allows them to breathe air without the aid of water. The only time the Piramboia don’t breath through their lungs is when they are breeding. At this stage in their lives, they rely on extra capillaries in their pectoral region and their gills.

Unfortunately, much remains unknown about this rare, unique fish. Breeding in captivity has never been accomplished, and there are quite a few people who keep aquarium specimens.

Lungfish are escape artists. If a lungfish is in an aquarium, it will try to escape and if it does, it will survive and find its way around the house and hide.

Locals don’t catch lungfish for food, and most encounters with these oddballs are during the dry seasons. Local children and pets often find the burrows of these fish and attempt to dig them up. Since the fish are hibernating, they are vulnerable. Otters can usually find their burrows as well, and will help themselves to an easy meal if they can dig the lungfish from its nest.

Because of their special lungs, Piramboia are high interest specimens for evolutionary biologists, as they may hold the unknown evolutionary link between fish and air-breathers. Scientists are still studying this fish to discover what genetic features have survived and evolved into the mammals of today.

Photos copyright: Fishbase.org and Wikipedia.org

Cuiu-Cuiu - Pre-historic fish of the Amazon

In the Amazon, there are some truly enormous fish that can intimidate even the most experienced fisherman or aquarist. The Oxydoras niger, or Cuiu-Cuiu, is a huge black-brown catfish that is perhaps the most pre-historic looking of Amazon fish. This catfish is also called a “black doradid”and remains one of the favorite large cats of aquarium keepers.

 The Cuiu-Cuiu grows up to 3 feet long (though 2 feet is average) and can weigh over 40 pounds. This catfish has a thick, leathery, black skin with sharp thorns jutting from the sides of their bodies, called scutes. This fish looks like a moving armored vehicle when it sifts through the bottom of the Amazon, looking for snails and insects to feast on. The Cuiu-Cuiu’s diet is mostly insects, snails, earthworms and berries from overhanging trees.

The Cuiu-Cuiu prefers soft water and has some of the best tolerance to temperature change in the Amazon. The Cuiu-Cuiu can tolerate temperatures as low as 10 degrees celsius, and as high as 30. As a result of its inherent hardiness, this catfish can live up to well over 10 years, which is substantial in the Amazon. The Cuiu-Cuiu’s tolerance to such temperatures also makes it a perfect survivor during the dry season when water temperatures soar as they drop very low under the hot equatorial sun.

The Cuiu-Cuiu is another Amazonian fish that takes on a yearly migration in the name of finding a mate and spawning. Like the Jaraqui, the Cuiu-Cuiu swims many miles to reach selected spawning sites where many Cuiu-Cuiu gather. The actual breeding process is still largely unknown in this species, but if this catfish behaves like other catfish, then the Cuiu-Cuiu probably makes a nest where the male guards the eggs until the fry are old enough to venture out on their own. No breeding has occurred in captivity and it’s very hard to tell the male from female apart.

Locals only rarely use this catfish as part of the diet. Not much of this fish is exported, so the Cuiu-Cuiu’s numbers aren’t threatened by over-fishing. This catfish is susceptible to many nematode parasites, which makes it dangerous to eat without proper cooking.

This catfish is so hardy that small populations of it have been found as far north as Florida. Of course, these populations came from former aquarium inhabitants that were set free. In larger numbers these catfish can compete with natural wildlife for resources and harm the delicate biological cycle of Florida’s wetlands.

 In fish stores, the Cuiu-Cuiu is sold as a 2-4 inch specimen that looks almost like a plecostomus. Beginning fish keepers don’t understand the immense size this fish can reach, as it often outgrows its tank.  Having too small a tank is dangerous because this strong cat can literally burst the sides of a tank that’s not built to withstand its swimming or darting.

Another interesting feature of this catfish is that it will “talk” to other catfish. The Cuiu-Cuiu will emit a low croaking sound. At night, locals can often hear this fish emitting this noise which is easily mistaken for a toad. This fish also makes this noise when it feels threatened or when it’s being handled. The Cuiu-Cuiu can also grind its dorsal fin against the socket where it connects to its body, producing a very distinctive grinding sound.

Photos copyright: Fishing-khaolak.com and Seriouslyfish.com

Arowana - The Legendary Water Monkey of the Amazon

One of the most treasured fish of the Amazon is the Arowana. The Arowana is a long flat silver fish with an enormous mouth, big eyes and trailing tapered fins. Inside the Arowana’s mouth, you can find a large bony precipice which gives the Arowana its trademark: a bony tongue. The Arowana’s head is bony as well and very well defined. The Arowana’s big eyes give the fish unsurpassable accuracy in hunting. Scientists think the Arowana may have the best sight of all fish in the world.

 

This fish certainly has had a lot of time to evolve its senses. Arowana fossils in the Amazon area have been found from over 170 million years ago. The Amazon Arowana’s predecessor was found in Africa over 220 million years ago. Over time, the Arowana has remained almost the same, making the Arowana a “living fossil.” Arowana can also draw oxygen into their swim bladder, which is lined with capillaries similar to those found in lung tissue.

 

There are three subspecies of Arowana in the Amazon River, all originating from the Osteoglossum. There are other species of Arowana in Asia and Australia. The Asian and Australian Arowana are a little shorter and stockier than the Amazon Arowana.

 

Arowana fish reach around four feet long and can weigh as much as 30 pounds. They are relatively flat, long and have silver bodies. Their tapered fins vary from individual to individual. Black Arowanas have black trim on their tapered fins. Silver Arowanas can have very little color or a lot of color, which can range from dark grey to a light tinge of pink, especially when they’re juveniles.

 

All four feet of the Arowana is pure muscle, allowing the Arowana to dart at speeds over 25 mph under the water to catch its prey.  The Arowana can often be seen leaping gracefully from the Amazon River, reaching towards a stray branch for a small bird or insect. It’s not uncommon for an Arowana to see the shadow of a boat or human along the edge of the Amazon and leap in anticipation of food. While they cannot eat humans, it’s certainly a sight to see the Arowana leap!

 

Arowana have a rather complicated life cycle. Ironically, this king of the Amazon starts out as a very fragile fish. Until they are a few weeks old, the infant Arowana have egg sacs attached to their ventral side which supplies food and nutrition. At this time, young tiny Arowana stay together in groups of 10 or less, finding shelter in the roots of the Amazon tree system. Young Arowanas eventually lose the egg sac at around 5-6 weeks, and at that point, begin to feast on bugs and any small tetras they can find.

 

Once they make it past the first few months of survival, the Arowana is a very hardy fish that grows rapidly. By the time it’s a year old, a well-fed Arowana can be over 1 foot long. This rapid growth gives the Arowana its survivability in the harsh Amazon River where most predators are well over 2 feet long!

 

In the wild, Arowanas tend to stay in loosely-knit groups that have been established through territorial battles. Both male and female Arowanas defend their territory by nipping, body-slapping and charging displays at other Arowanas. When they are old enough to breed (suspected to be around 1.5 to 2 years old), Arowana male and females pair up and build a circular nest in the mud of the Amazon. The female will lay eggs and the male inseminates them in the nest. When the viable eggs are fertilized, the male will gulp them into his mouth and keep them there. Each male carries around 10-20 eggs. When the eggs hatch, the male will let the young fry swim out several times before he finally lets them go completely.

 

Commercial Arowana breeding requires very specialized care, and massive outdoor mud ponds. Most Arowanas from Asian stock are micro-chipped for trade and import and some can go for as much as $6000! South American Arowanas aren’t as highly prized but are just as beautiful and have just as much personality as the Asian species.

 

Full adult Arowanas can leap as high as 6 feet from the water, using their missile-shaped bodies of pure muscle to lift them gracefully into the air. In aquariums, it’s always a challenge to keep Arowanas in the water. Many times they’ll leap to their handler’s proffered food and some have even been trained to leap for their food. The Arowana isn’t for the inexperienced aquarist. A large tank (over 200 gallons) is required, and there are few tank-mates suitable for the Arowana. The rewards of keeping the Arowana are wonderful if you have the time, room and patience!

 

Photos copyright: Aqua-fish.net and Wikipedia.org 

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