Tambaqui and Pirapitinga
Which is Which?
Amazon fish often seem mysteriously difficult for anglers to identify because of seemingly indecipherable confusion about their names. Local names for the same fish often vary by region, while completely different fish may be called the same name in different areas. Sometimes fish species may be very similar in appearance, complicating even scientific classification, while at other times, the amazing diversity of species alone may be enough to confound simple field identification.
This is certainly the case with the largest members of the of the Characin family, tambaqui and pirapitinga. Not only are they commonly confused with each other and a whole range of other smaller characins (called pacu as a group), but they have even undergone changes in their scientific names and classification in recent years. These two giants (formerly classified as Colossoma and currently split into the genera Colossoma and Piaractus) are unique not only in being (after the arapaima) the two largest scaled fishes in the region but in occupying an ecological niche that has no parallel anywhere else in the world.
Tambaqui - Members of the sub-family Colossoma of the Characidae, tambaqui (Colossoma macroponum) are oval-shaped, physically built like a stocky permit or jack. They have a golden to olive green back and an inky purple to black ventral area. An omnivorous characid relative of the piranha, tambaqui have dazzling teeth that look eerily like a set of human dentures. These fish have amazing jaw strength as they often feed on rock hard jungle seeds. They can crush a 4/0 saltwater hook as if it were made of baling wire. These fish are so strong that the locals fish for them with stout green saplings secured to 120-pound monofilament, heavy cable and 6/0 tuna hooks!
Tambaqui can get huge. Specimens of 3 feet in length and weighing in at over 70 pounds are not exceptional. Unfortunately for the sportfisherman, these highly prized (and pricey) food fish are heavily harvested by commercial fishermen, especially during their spawning migrations when they are at their most vulnerable. This doesn't leave too many options for a successful sport fishery, although pockets of these big characins are sometimes encountered by peacock anglers in small tributaries of some peacock bass rivers.
Pirapitinga — Thankfully pirapitinga (Piaractus brachypomus) are not as highly desireable a food fish and they are not heavily harvested in any organized manner in the Amazon basin. This fortuity enables sportfishermen to readily access them in their low water habitat. Also a migratory species, these broad shouldered and brawny fish often reside near fast current and are perfectly fit for such an environment. They have huge anal fins and extremely wide, thick tails. When hooked they use their powerful oval body against the current and make incredible heart stopping runs. With the force of fast water added to their own weight and power, they can be almost unstoppable.
Typical tackle for these fish is similar to that used for big peacock bass, dorado and payara. Thirty to fifty pound-braid and an equally-stout wire leader are essential. When water levels are extremely low, thereby denying them access to fruit from overhanging branches, they will opportunistically take a variety of lures. Some of the best include; Blue Fox Vibrax spinners (#5), Yo Zuri Surface Squirt, and 5-inch jerk baits. When the waters rise just a bit, pirapitinga will quickly apprehend a sweet piece of jungle fruit dead drifted on a big circle hook!
Pirapitinga can be taken on fly with a fast action 9 or 10-weight fly rod. They will take some of the same flies listed in the dorado section, including heavily-dressed 3/0 Cloussers and Muddlers (they seem to prefer blue for some strange reason). They also take "fruit flies," which are nothing more than brightly-colored deer hair (yellow or bright orange are good) spun and clipped to look like a chestnut-sized jungle fruit.
Pirapitinga are one of the best fighting fish in freshwater. Recently explored fisheries in Brazil have given easier access to sportfishermen. It won't take long for the word to spread and for these big bruisers to be recognized and valued for their extraordinary sportfishing prowess.
Telling them apart
Pirapitinga are more deeply rhomboidal than their evenly oval cousins. Their coloring is more muted, typically a light blue-gray to steely gray above and a darker gray to brownish gray below. The pirapitinga's dentiton is different as well, sporting a second row of molars in the upper jaw as opposed to the tambaqui's single row.
The Fish, the Forest & the Fruit
Tambaqui, the largest of all the characins, are creatures of the Amazon's flooded forest. The pulsative nature of Amazonia's lowland rivers creates vast flooded forests during the region's long rainy seasons. Rivers flood their banks and inundate adjacent varzea (flooded) forests. As though a dinner bell were rung, the area's wildlife flocks to the new border between land and water to feast on a banquet of flowers, seeds and fruits
Tambaqui are an integral part of the varzea's life cycle. Feeding on the bounty of fruits and nuts that drop into the water, they become an important mechanism for seed dispersal. Many jungle fruits contain an outer pulp and a hard inner seed(s). When small seeds are ingested they are not always crushed by the tambaqui's powerful jaws. Passing through the fish's digestive system, the seeds are scarified by the process and then excreted, often far from the parent tree. Later, when the waters recede, the prepared seed is able to sprout in the newly exposed dry land, far from where it was dropped.
When the varzea drains, well-fed tambaqui leave the small tributaries and form large migrating schools in the main rivers. Their large fat reserves, built up during the rainy season are used during their upriver journeys and ensuing spawning. It's believed that their eggs are dispersed in the grassy levees along the river. The dry season provides slim pickings for the small fraction of tambaqui who do not migrate. Those remaining in small tributaries will often turn to small fishes and insects to help fill their empty stomachs, providing an opportunity for lucky anglers.
Tambaqui are an important food fish. They have recently begun to be raised in fish farms to meet the market demand. This bodes well for the future of natural populations.
What do they eat?
Although known primarily as fruit, nut and flower eaters, pirapitinga, when the waters recede will give up their vegetarian ways for a more opportunistic diet. With their main food source gone, they will eat small fish, invertebrates, leaves or grass. Perhaps the oddest thing is their penchant to eat Yo-Zuri surface squirts. These day-glo plastic baits are designed to resemble saltwater squid. What makes them eat these lures? Surely they've never seen squid in their native waters!