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What's the Deal with Brazil's Round Fish?

The members of the pacu family may be the most challenging and underrated fish in fresh water.

What's the Deal with Brazil's Round Fish?
(Courtesy of Untamed Angling)

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At least 20 years ago, doubtful about which fishing lines and lures to choose from our untidily masculine fishing camp—on the bank of Brazil’s mythical Touro Morto River, located in Mato Grosso State’s Pantanal, one of the largest wetlands in the world—I used to ask: “Grandpa, what are we going to fish for today?”

My paternal grandfather, my great fishing teacher, always had an answer for every new angling situation that arose in the diverse environment of the Pantanal. The old man’s hair was gray, his face lined by long years. His impeccably arranged fishing tackle was the only sign of neatness around us. Not even looking at me, he would say, “I don’t know. The river and the jungle will let us know. Be ready for anything.”

His answer descended on me like an endless sea of questions in my already doubt-ridden young mind. I could not seem to grasp so many possibilities. Be ready for what? Everything? In the Touro Morto, there were things swimming down below that I hadn’t even imagined.

An elder of the Terena tribe who used to guide us on those expeditions always said, “The jungle brings life, life to the earth and life to the water. The fish know when the jungle is feeding them. They wait, and the jungle provides.”

The wise Terena guide, whose name translated to “Grasshopper,” was an accomplished navigator in the watery maze of the flooded Pantanal jungle. He knew exactly where to go, and when, and which fish to track down. His was an ancestral wisdom, passed down from one generation to the next among those native peoples whose origin was the Pantanal.

Grasshopper’s teachings will never be found in any book. However, as survival-enabling voices, they have been transmitted for centuries among Brazil’s indigenous Terena, Guató, and Payaguá tribes. A Terena fisherman always returned from fishing trips with something in the bottom of his canoe, which had been carved out of a single cambara tree trunk.

From Grasshopper and from my grandfather, I learned that angling in the jungle forces us to open our minds, to understand and to be more sensitive to the incredible natural phenomena taking place around us. Jungle anglers rarely pursue a single species. We must be mindful of all possibilities made available by this complex environment.

On each new fishing journey, Grasshopper displayed the rare perception of someone who was deeply in touch and interactive with this environment, of which he and several previous generations were inseparable parts. His tribe had already battled all kinds of threats, from ambitious ranchers yearning for new land to feed their huge cattle herds, to gold prospectors pursuing the riches lying below the ground. Land is sacred to these indigenous peoples.

Grasshopper used to say: “The white man is only after riches that fit into his pockets. We have far vaster riches, which cannot be measured and go as far as the eyes can reach. All of our children will be entitled to them one day, until white men come to strip us of them by force.”

A scenic image of a fly angler in a Brazilian river.
(Courtesy of Untamed Angling)

Jungle Targets

In those jungle rivers where I fished with my grandfather, our primary objectives were freshwater dorado (the king of South American rivers), pacu (the round fish), surubi (an amazing species of striped catfish), and piraputanga (Brycon spp.), which together comprise the top of the aquatic food chain.

The annual water cycle floods and drains the forest, and controls the lives of all the flora and fauna there. Understanding those alternating cycles of flood and drought—as if they were a constant dance that changed each river up-, mid-, and downstream—is key for any angler who wants to start playing the game with all the cards.

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Although I was constantly obsessed with the ferocious king of fishes—golden dorado—Terena fishermen taught me that there are cunning, powerful alternatives that are without a doubt more challenging.

One day Grasshopper said, “Boy, look at the trees. Look at the animals on them. What are they feeding upon? Look at that tall tree. It is heavy with nuts.” Fruit fell down into a backwater near the riverbank, making a distinctive “plop” sound. Immediately, Grasshopper grabbed a long bamboo rod, took out a small green nut that he carried in the pocket, used it to bait an old, darkened hook, and lobbed it into that backwater—“plop.”

Then he said, “Start counting.” I made it to two, and after something almost jerked me into the river, Grasshopper cried, “Pacu!” The fishing line sounded like the strained string of an old guitar, and the long bamboo rod unbalanced even Terena from his standing pose in the canoe. Both of us nearly ended up swimming.

A calamitous fight ensued, with Grasshopper jumping from stern to prow, helping with the paddle to keep us near the fish, and to keep the fish away from the roots and trees in the water. The fish was so powerful that it plunged the whole rod underwater. It rotated, passed under the canoe, went for the bottom of the pool, and spun us 180 degrees in its attempts to get rid of the hook. Finally we lifted that giant round fish to the edge of the canoe, and I ran my hand along its muscled flanks. It was as perfect and strong as a well-fed herd animal. It would feed Grasshopper’s family for days.

A fly angler hooked up to a fish in a blue river, wading waist deep.
(Courtesy of Untamed Angling)

River Pigs

My early experiences with the various round species found in the Amazon jungle—pacu, pirapitingas, and tambaquis—were random and, frankly, based on opportunities that sprang up at certain moments. I watched pacu rise to the water’s surface in order to feed on flowers and fruits below the tree crowns of massive lapachos, fig trees, and cashew trees. It was a gift I couldn’t ignore. It took decades for me to learn where and how to make these memorable moments repeat themselves—pacu became a potent elixir I needed to sample over and over.

These fish are voracious omnivores and will consume just about anything edible. The river is a part of the jungle, and these are by any definition jungle creatures, thriving in deep, shady pools and in slow-moving stretches of deep water, where they sometimes swim in schools. The right food source might also bring them into rapids, pool edges, and sandy shorelines, where they swim and feed like large bonefish.

Of all the fish in the Amazon region, pacu probably display the highest degree of interaction with the jungle. No other fish make such full use of the food sources provided by the terrestrial ecosystem. They take shelter in the shade of trees and under fallen logs and sunken roots. They devour absolutely everything the jungle has to offer: leaves, fruits, flowers, seeds, other fish, detritus, large insects (both terrestrial and aquatic), and small vertebrates such as frogs, rats, and even baby birds. Because of this behavior, pacu are known to many indigenous peoples as “river pigs.”

After thousands of years of evolution, the life cycles of pacu, pirapitingas, and tambaquis are finely attuned to the flood and drought cycles of the rivers where they live. These fish love the flooded jungle, and faced with even the slightest sudden rise in the water level, they disappear into the floodplain forest. The flood cycles, which are times of plenty, are key to the growth of the fish and the buildup of fat.

Pacu have keen eyesight and long memories, and they keenly observe what is going on outside their watery realm, often watching monkeys and macaws loudly helping themselves to the banquet in the treetops, raining down leaves and fruits. They seem to anticipate a meal, watching a flower petal or other morsel spinning slowly down through the air, and meeting it the instant it hits the water.

With these finely tuned senses, pacu can be frustratingly difficult to catch, and most of my early encounters with a fly rod in hand brought quick attention from the pacu, a rigorous inspection of my offering, and then a casual refusal.

“What clever pigs,” I’ve whispered many times in defeat.

A fly angler holding a pacu in a river.
(Courtesy of Untamed Angling)

Characid Family

If you look at a map of the native range of the pacu family, you’ll see a massive area in South America that extends from the northern Amazon (Venezuela, the Guyanas, and Suriname) down to southern Bolivia and northern Argentina in the flat expanses of the La Plata river basin. This enormous range of habitat creates incredible species diversity, offering opportunities for fly fishers to use tackle ranging from light 3-weight outfits and small dry flies for small silver pacu, up to 10-weight rods with flies tied to imitate fruit and nuts to attract gigantic tambaquis, or black pacu. These are the largest fish in the Characid family, with some specimens reaching 60 pounds.

In fact, there is an enormous variety of round fish that may be pursued with fly rods in the Amazon region. By now, you will have noticed that this is how I like to name the various species of pacu, from the small silver pacu (an accomplished jumper), to the rubber pacu that feeds on algae in the rapids (curupete), to the big pirapitingas (called red-bellied pacu as juveniles), to the massive tambaqui (the largest species of round fish).

Interestingly, the pirapitinga and tambaqui have been introduced to Florida as escapees from the aquarium trade, and to other parts of the world for purposes of aquaculture—they are delicious food fish.

My passion for hunting these fish in their native environment began decades ago. I remember a perfect sun-drenched late afternoon when the tops of the trees along the river were scattering the sunshine and reflecting luminescent green hues on the placid surface of the water. I had chosen light tackle to fish for the Brycon species along the shoreline. These are known as matrincha in Spanish, and are sometimes called South American trout.

But as I’ve found so many times, we are not the ones making the choices in the jungle—rather, we are chosen. I was wading and casting toward the shore, when the wind behind me carried the fly beyond the intended target, snagging the sharp hook in a small branch. As I wiggled the rod tip to free the hook, the fly fell from the branch in the most natural way, just as if a leaf or insect had fallen to the water’s surface.

I remember the ensuing scene in slow motion: A dark back cut through the surface, the fly vanished, and in an instant I felt the weight of a huge pirapitinga. I had no time for a reaction or even to think of setting the hook, as the fish grabbed my fly and made a fierce run for its life.

Round fish seem to have two personalities in a single body. They are cautious about accepting food, they often approach flies slowly and timidly, and they show remarkable delicacy when taking small flies from the surface. But once hooked, they become different fish completely, unleashing a brutal and unstoppable power that tests the limit of your tackle each and every time.

Pacu are often called “freshwater permit,” and many people assume that’s the case merely because they are difficult to catch, but the similarities go much deeper than that. It’s their cautious, skittish behavior, and then their tremendous change in character, that draws the comparison. Fish with this body shape are heavily muscled and can position their bodies like sails in the current, making for tough fights that few other fish can replicate.

Setting the hook in a pacu is a very different experience than what you might be accustomed to. Unlike saltwater permit, which have rubbery lips conducive to hooking, most round fish have mouths filled with teeth. The mouths of tambaquis (black pacu) are filled with almost human-looking teeth, set side by side. These are the teeth of omnivores, used for crushing and grinding food. They aren’t especially sharp, but they can still cut your line as easily as pliers, and they also make it difficult for a hook to find purchase.

The hook-set requires a lot of concentration. If you take your cue from how gently the pacu takes the fly—similar to a trout—and use the infamous “trout set,” the opportunity is lost. However, if you take into account the teeth and set too hard, the fish can easily snap your leader. I can’t tell you how many times I’ve seen anglers break 30-pound-test tippet the first time they try to set the hook in a big pacu. Angling for these round fish means walking the razor’s edge. There is no alternative. They bite, chew, and tear apart any monofilament fishing line. But they won’t take a fly fished on wire—they are too smart for that.

I advise a short, firm hook-set with the rod tip held low, with the line hand poised and ready to allow line to slip after that hook-set, to avoid breaking the line. The motto of a great Argentine fisherman and friend of mine applies here: Te haces el macho y te rompe todo. (If you play the macho man, you’ll break everything.)

After the strike and the initial run, the battle is often interrupted by submerged trees, roots, rocks, and holes where the round fish attempt to hide. In this way, they remind me of groupers in the ocean, which are notorious for snatching a bait and then retreating into a hole or crevice from which it’s nearly impossible to extract them. Like groupers, pacu seem to have mental maps of all the obstacles in their territory, and the first run is often directly toward their safe room.

While other jungle gamefish such as dorados, payaras, and matrinchas migrate frequently in search of food, round fish are much more territorial, especially in the mountain headwater streams where the biggest pacu seem to reside. In the more heavily fished lowlands, deltas, and swampy areas, you tend to find younger fish.

A collage of images of pacu fishing in Brazil.
(Photos courtesy of Untamed Angling)

Food Sources

Round fish are much like other omnivores—pigs and bears come to mind, as both can convert a wide array of food sources into muscle and fat. The diet of a pacu depends on the local environment, and their versatility means that while they may be nibbling on a leaf one moment, they may dash off in pursuit of small baitfish the next.

When pacu are actively feeding, they are often seen patrolling close to the water’s surface, a behavior resulting from competition with members of the Brycon genus (matrinchas and yatoranas), which often swim much faster when feeding. Round fish don’t like these types of quick decisions, so they often stay close to the surface, where they can get a good look at food items coming at them from the terrestrial world.

If a pool provides food at the surface (leaves, fruits, and flowers) and also in its depths (baitfish, crabs, and sculpins), large pirapitingas in particular will make full use of the entire water column. Like all gamefish, they gravitate toward the most consistent food sources.

If a pool does not provide food from the vegetation growing along its banks, round fish will not hesitate to seek faster, shallower waters where they can feed on algae, mosses, weeds, and other aquatic vegetation dislodged by the current. In this situation, the fish feed like trout, holding in position in the current and carefully inspecting insects and whatever else they find flowing downstream.

They move from side to side to feed, sometimes plucking gingerly at items on the surface. Rubber pacu commonly feed in the rapids, intercepting drifting pieces of aquatic vegetation. A large pirapitinga displaying this same kind of behavior in a crystal-clear river is one of the most thrilling scenes I have ever witnessed while angling in the jungle.

Headwaters

To stand any sort of a chance to catch these round fish on flies, you need clear water so you can spot the fish and so they can easily find your flies. In the turbid lowland rivers tainted by industry and agriculture, there are still many round fish, but catching them with hook and line is mostly an accidental occurrence.

However, the clear headwaters of Amazon region rivers—such as the Sécure and Pluma in Bolivia and the Juruena, Roosevelt, São Benedito, and Xingu in Brazil—are perfect laboratories for watching, understanding, and presenting flies to these wary gamefish. Bolivia’s Isiboro Sécure National Park, which contains numerous mountain rivers with crystal-clear waters, lies in a region where Amazonia joins the Andes mountain range.

This may be the perfect environment for fly fishing for pacu. In Isiboro Sécure National Park, I’ve been able to use all my previous experience in the Río de la Plata basin to hunt round fish in a pristine environment, sight fishing with surface flies that imitate large insects, flowers, or nuts. I consider this the apex of my efforts to fly fish for all types of pacu, but especially for the giant tambaquis that swim in the park’s clear, placid headwater pools.

Watching the pacu feeding—sheltered in one of the most pristine aquatic environments in all of Amazonia—made me understand what Grasshopper tried to teach me so many times. He was absolutely right. The jungle provides for the fish, and it also provides us with new challenges and new understandings each and every day. A good fisherman first understands the jungle, and then translates that knowledge into a fly-fishing opportunity. We wait, and the jungle provides.

A black and white image of a leopard sitting next to a river.
(Courtesy of Untamed Angling)

Book Your Destination

The best place to sight fish for giant black pacu is in the clear headwater streams of Isiboro Sécure National Park in Bolivia. For shots at multiple species including red-belly pacu and rubber pacu, consider Kendjam Lodge in Brazil.

Kendjam Lodge – untamedangling.com

Tsimane – untamedangling.com

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Pacu are omnivores and often feed on nuts, fruits, and flowers that fall from overhanging trees. Your guide will provide flies tied to match the shape, color, and density of these food items.


Rodrigo Salles is a partner in the outfitting business Untamed Angling. He lives in Manaus, Brazil. You can watch him fish for payaras, peacock bass, and wolf fish in the feature-length documentary Blood Run.




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