Piranha (Pygocentrus)

The Pygocentrus genus of piranhas is home to some of the world’s most fascinating and dangerous fish. They have an image as vicious predators because of their powerful jaws and sharp teeth, but these animals are much more than just violent animals.

Piranhas in the wild are frequently misinterpreted. Even though they have a fierce nature, they don’t always live up to the horrifying stereotype that is frequently presented in stories and films. Even seasoned aquarists can be surprised by the complex behaviors that these fish exhibit, as they live in schools and are actually quite social.

The needs of piranhas in aquariums must be understood and special care must be taken. Every element, including their diet and preferred habitat, is vital to ensuring their success in captivity. Knowing about Pygocentrus piranhas offers a unique window into the world of these fascinating fish, regardless of experience level.

Characteristic	Description
Scientific Name	Pygocentrus
Family	Characidae
Habitat	Freshwater rivers in South America
Diet	Carnivorous
Size	Up to 35 cm
Temperament	Aggressive, especially in groups
Aquarium Size	At least 200 liters
Water Temperature	22-28°C
pH Level	6.5-7.5
Life Span	10-15 years

Preface

One of the most well-known freshwater fish in the world, the red-bellied piranha is renowned for being an ravenous predator that can swiftly rip flesh from bone and pose a threat to any animal that ventures into its waters. Because of this, most public aquariums display this "bloodthirsty" creature; macabre Hollywood films have been released; and the species has gained popularity in the aquarium trade.

Herbert Axelrod (1976) asserts that the myth originated with Theodore Roosevelt’s 1913 visit to the Brazilian Amazon. Many journalists accompanied him, and the Brazilians orchestrated several ruses, including the claim that the president had "discovered and discovered" a new river that was subsequently named after him. Rio Roosevelt or Rio Teodoro are the names given to one of the Aripuanão River’s tributaries, which was selected for the project.

When Roosevelt arrived at the river, the Brazilians had a surprise in store – an area of ​​several hundred yards was blocked off, and over the course of several weeks, fishermen released hundreds of adult piranhas into it and isolated them there. They told the president that he and his men should refrain from entering the water, as they would be eaten alive by the terribly vicious fish. Naturally, this news was met with skepticism, so a cow was driven in. This sparked a spectacular, frantic fight for the right to get "their piece" among the trapped, hungry piranhas. After this event, newspapers were filled with stories of the scary, carnivorous fish, but there was not a single record of a person being killed by wild piranhas.

Information from various websites and forums currently dedicated to this subject indicates that piranhas and their relatives have experienced a relative boom in captive keeping during the past few decades. There are now many different species available, but the majority are expensive, wild-caught species that are out of reach for most hobbyists. In contrast, Nutterer’s piranhas are bred for commercial use; coin-sized adolescents are sold for relatively little money for a fish that needs specialized care and upkeep that is ultimately costly. This is a fantastic aquarium occupant for enthusiasts, but careful consideration and research are necessary before making a purchase.

For several reasons, Nutterer’s piranha has proven to be challenging to identify. For instance, Pygocentrus piraya and Pygocentrus cariba have different morphological characteristics and are native to particular river basins—the San Francisco in Brazil and the Orinoco in Venezuela/Colombia, respectively. Pygocentrus nattereri is a species with an extraordinarily broad distribution, and even individuals within the same population can differ greatly in color. Fish that live in blackwater environments typically have darker colors and less reddish-orange pigmentation than fish that live in clear or white water. Fish coloration also varies based on the type of habitat.

The shape of the head and body, the existence or absence of dark spots, and the mesh pattern on the sides and fins can all vary in adult fish morphology and structure.

All species of piranhas (Pygocentrus) share comparable maintenance, feeding, and reproductive circumstances.

Natterer"s Piranha / Common Piranha / Red-bellied Piranha (Pygocentrus nattereri) Kner, 1858

Nattereri: derived from the name of Johann Natterer, an Austrian naturalist (1787–1843).

Habitat and Range

Presently distributed across the majority of the Amazon Basin (Brazil, Ecuador, Peru, Bolivia, and Colombia), the Essequibo River (Guyana and Venezuela) in the northeast, the Parana River (Brazil, Paraguay, and Argentina), and the Uruguay River (Brazil, Uruguay, and Argentina) toward the south.

Large rivers, tiny tributaries, oxbow lakes, floodplain lakes, and ponds are examples of habitats.

Description

Each member of the genus Pygocentrus, or piranhas, is identified by having a massive lower jaw, a small mouth, and extremely sharp teeth on both jaws.

These fish are extremely fast due to their wide, laterally compressed body, small pelvic and pectoral fins, an elongated anal fin, a strong forked tail, and small scales. It’s all jagged inside, like a cheese grater. Additionally, between the dorsal and caudal fins is an adipose fin, which is unique to caracins.

Adults are colored brightly. There are many variations, but generally speaking, the anal fin, throat, and abdomen are reddish-orange, while the body is silvery with golden flecks below. The top is gray with a metallic sheen. There are numerous shiny specks on the scales and dark patches on the sides.

Size: Maximum Standard length 250 – 350 mm.

Behavior and Compatibility

Even though mature piranhas are not prone to hunt smaller fish, they are best kept alone in a species aquarium. Although it’s commonly believed that wild P. nattereri hunt in voracious schools, clusters are typically formed by juveniles only. It is best to buy a single specimen or a group of five or more, as older individuals tend to form loose groups and establish dominance hierarchies.

Aquarium

Only appropriate for sizable aquariums.

For ease of maintenance, some aquarists choose to keep this species bare-bottomed; however, regular aquarium sand or gravel make suitable substrates. Other décor options are mostly up to personal taste, but live plants could be consumed—especially if the fish decides to spawn. Lighting can be low or high, depending on preference; it is not essential.

Since all true piranha varieties tend to generate large amounts of waste, using one or more small external filters is imperative. Since adult fish are known to damage underwater equipment, if possible, buy filters with a built-in/flow heater or at the very least, make it unbreakable. For this, a sump/SAMP system functions well.

Water parameters:

Hardness: 2–12 dHG; pH: 5.5–7.5; Temperature: 24–28 °C.

Try to add or remove between 30 and 50% of the tank’s volume every week, and always use extra caution when doing maintenance or harvesting fish.

Diet

Rather than being solely carnivorous, Pygocentrus species are better understood as opportunistic generalists.

Live fish, along with other aquatic invertebrates, insects, nuts, seeds, and fruit, make up the natural diet. There is only one row of triangular, sharp teeth in each jaw, which are used like blades to pierce, tear, shred, and crush.

Attacks on live animals that enter the water are extremely rare and mostly involve accidental bites or situations in which a large number of these fish remain in small bodies of water during dry periods. They do, however, occasionally attack sick or dying fish and consume the remains of the skeletons of large species.

Juveniles in the aquarium can be given bloodworms, small earthworms, crushed shrimp, etc., while adults will take large earthworms, mussels, pieces of fish flesh, etc.

Mammal or poultry meat contains certain lipids that the fish cannot adequately digest, which can lead to excess fat deposits and even organ degeneration. For this reason, the species should not be fed these meats. Furthermore, feeding fish like small goldfish or viviparous fish—which are generally low in nutritional value and carry a risk of disease—has no benefit.

Sexual Dimorphism

Compared to men, females typically mature at a larger size and have a more rounded body type.

Breeding

A sudden temporary rise in water level occurs during the low water period in November and December, while the second breeding season occurs during the rising water levels at the start of the rainy season in wild populations. The best places for spawning are flooded coastal vegetation and lake beds in floodplains.

Breeding Nutterer’s piranhas in an aquarium is not too difficult. When a child reaches sexual maturity, their body length should be between 100 and 150 mm. It is probably best to start with a group of six or more fish if you are unable to locate a breeding pair. This will allow pairing to occur naturally. Spelling has been observed to be triggered by significant cold water temperature changes in certain instances, but it has also happened spontaneously in other cases.

When a male is ready to breed, he becomes territorial and centers his chosen area by making a depression in the substrate with his mouth and tail fin. It is also possible to "mow down" aquatic plants, and the resulting "nest" is protected from other males.

When females who are ready to spawn begin to show interest in what is going on, both the male and the female eventually darken in color. The male deposits the eggs in multiple batches and guards them; occasionally, the female assists. Many pairs can spawn simultaneously in very large tanks.

After hatching in two to three days, the larvae start swimming freely on the fifth day. It is currently thought to be the most effective method for moving the fry to smaller nursery tanks. Microworms or Artemia nauplii are suitable as an initial food. It will also need a daily water change of roughly 10% of the tank volume.

The difference in growth rate causes the fry to turn into cannibals; when this happens, they should be moved to larger tanks in groups of equal size.

Consider your options carefully before beginning to breed, as you may raise more than 1000 fry and then run out of space.

Pygocentrus Piraya Cuvier, 1819

The orange-red color that rises along the entire length of the fish’s body, sometimes reaching the lateral line, is what makes this piranha unique.

Distribution and natural habitat

Limited to the eastern Brazil region of the São Francisco River basin, which includes sizable tributaries like the Velhas and Grande rivers.

Inhabits large artificial reservoirs created by dams, floodplain lakes, small tributaries, and river channels.

Size: 300 – 350 mm.

Aquarium

Only fit for the biggest private aquariums or public exhibition.

Water parameters:

20 to 28 degrees Celsius; pH 6.0 to 8.0.

Breeding

Although unrecorded, it is likely that they reproduce similarly to their relatives P. nattereri.

Black Piranha / Black-spotted Piranha / Cariba Piranha (Pygocentrus cariba) Humboldt, 1821

This piranha is easily recognized by the black spot on its body located directly behind its gill cover.

Distribution and Natural Habitat

Limited to the Colombian and Venezuelan Orinoco River basin, which includes sizable tributaries like the Inirida, Guaviare, Meta, Tomo, Casanare, Apure, and Guarico Rivers.

Inhabits floodplain lakes, smaller tributaries, and wide river channels. Although it can also be found in clear water, many of these areas contain acidic, low-mineralized "Black Water." Nearly 600,000 square kilometers of seasonally flooded plains and forests make up the majority of its habitats, which are found in Venezuela and Colombia.

There are distinct wet and dry seasons, year-round high temperatures, and well-defined weather patterns.

Size: 250 – 350 mm.

Aquarium

These are the minimum specifications for a group of fish, and they are only appropriate for public demonstrations or the largest private aquariums. Measurements: 240 * 90 * 60 cm or equivalent.

Water parameters:

PH range: 4.0 to 7.0; temperature: 20 to 28 °C.

Piranha Palometa (Pygocentrus palometa) Valenciennes, 1850

Valenciennes described the species, but no proof of this has been discovered as of yet.

Distribution

Venezuela’s Orinoco River Basin.

There is insufficient evidence to establish or confirm the existence of this species.

Paper records that have been preserved are the only source of discoveries of this kind.

Though fascinating, piranhas are a misunderstood species. Their distinctive behaviors and significant ecological role are frequently overshadowed by their reputation as vicious predators. They are not the thoughtless killers that are frequently depicted, despite the fact that they are strong and aggressive.

Piranhas need close attention to their diet and surroundings in an aquarium setting in order to survive. It is important to honor their innate behaviors and social dynamics in order to protect their wellbeing. For committed aquarists, keeping piranhas can be a fulfilling experience with the right care and knowledge.

By recognizing piranhas for what they are, not for what legends have it, we can take advantage of the chance to get up close and personal with these amazing fish and discover more about their fascinating nature.

Freshwater fish called piranhas (Pygocentrus) are fascinating and sometimes misinterpreted creatures, distinguished by their strong jaws and pointed teeth. In reality, they are timid and would rather stay away from people, despite their terrifying reputation. Piranhas need special attention when kept in aquariums; these include having a large tank, adequate filtration, and a diet that closely resembles their natural eating schedule. Sustaining a healthy and flourishing piranha aquarium requires an understanding of their behavior and requirements.

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