#pirarucu

[marinememes]

My coworker took a full frontal picture of the arapaima at work and sent this in our group chat

[bethanythebogwitch]

It's big, it's strong, its scaly, it's this week's Wet Beast Wednesday topic! An arapaima, also known as a pirarucu or paiche, is any of four species of fish in the genus Arapaima in the order of bony-tongued fish. There is som ongoing debate about the classification of the species, so to keep thing simple, I'm going to use the most common species names of Arapaima gigas (the type species and most well known, and the one with the most confusion about its classification), Arapaima agassizii, Arapaima leptosoma, and Arapaima mapae. Because A. gigas is the most well-studied of the species, unless I say otherwise you can assume everything I say in this post applies to it.

(image: an arapaima)

Arapaimas are bony fish that retain several primitive traits, causing them to sometimes be identified as "living fossils". They are most notable for their size, with A. gigas being a contender for the largest freshwater fish in the world. The maximum recorded size for one was 3.7 meters (10 ft) and 200 kg (400 lbs), but most get to around 2 meters (6.6 ft) long and 200 kg (440 lbs). That average length is decreasing as overfishing of the largest individuals is resulting in a selective pressure for smaller sizes. In addition to their size, they are extremely strong and can move fast if needed. Arapaima are fully capable of leaping out of the water if disturbed or they feel their current pond in unsuitable. Because of their strength, specimens in captivity must be handled with care as they can easy break bones if they slap someone. They live in rivers and lakes in South America, where they are often the top predators.

(image: several anglers with an arapaima)

Arapaimas are obligate air-breathers and will drown if they can't get to the surface to breathe. This is accomplished with a specialized swim bladder. The swim bladder is filled with highly vascularized tissue, letting it act like a lung. This pseudo-lung opens into the mouth using a modified gill arch known as the labyrinth organ. Arapaima gills are too small to sustain them, but they can supplement their oxygen intake with the gills. Juveniles are born exclusively using their gills and transition into air-breathers shortly after hatching. Arapaimas can survive up to a full day out of the water. They typically surface to gulp in air every 15-20 minutes. Breathing makes a loud gulping sound that anglers use to target them.

(image: an arapaima at the surface)

Because of their ability to breathe air, arapaimas are top predators in low-oxygen environments. Non-air breathing fish are forced to slow down in water with low levels of dissolved oxygen as they can't get enough oxygen through their gills. Since Arapaimas breathe air, they can easily chase down lethargic smaller fish. They are especially potent predators during the low season, when water levels lower. A combination of rotting vegetation reducing oxygen levels and ponds getting cut off from rivers and losing a supply of oxygen lets the arapaima reign supreme. Arapaimas are primarily predators that feed on smaller fish, though they will hunt other types of animals and eat fruits and seeds. Even land animals aren't safe as arapaimas have been known to launch themselves out of the water to catch animals near the shore. A combination of sharp teeth and their bony tongues are used to debilitate prey.

(image: an arapaima with its mouth open)

Not content with powerleveling their attack stat, arapaimas also have excellent defense. Their scales have been compared to bullet proof vests. Each has a hard, mineralized outer layer over multiple layers of collagen fibers. These layers are all oriented at an angle to each other to provide extra strength. This orientation of layers is called a Bouligand-type arrangement and is similar to how plywood is assembled. The harder outer layers and flexible inner layers work together to allow for both strength and flexibility. These scales help provide protection form large predators such as caiman and small threats like biting piranha. They also like provide protection from other arapaima, as the fish are aggressive and will fight each other.

(image: a diagram showing the composition of arapaima scales. source)

You probably wouldn't expect a swimming tank of an animal to be a good parent, but you'd be wrong. Arapaimas work together in mated pairs to build nests for their eggs, then cooperate to guard the nest. Once the eggs hatch, the male will practice mouth brooding, keeping his young safe in his mouth. The female will also help by patrolling the area around the male to ward off predators. They secrete pheromones from their heads to ensure the young don't swim too far away. Eggs are laid either in in the low season or as water levels are starting to rise, ensuring that the young become independent during the high season.

(Image: baby arapaimas)

Arapaima are classified as "data deficient" by the IUCN. This means there isn't enough data to properly assess their conservation needs. They are known to be threatened by overfishing. Arapaima make up a large part of the diet of many South American populations. Habitat loss and pollution are also believed to threaten them. They have been introduced to many areas out of their native range and are an invasive species in placed like Florida, Malaysia, and India.

Does anyone else remember these cards? (image: the arapaima card from Weird n' Wild Creatures)

[b4catte]

My favorite character with a pirarucu (fish from my country) because i love both

[hst432]

ピラルク 鳥羽水族館

インフルエンザ予防接種のあとが痛痒い……

[diy-fire-water-pups]

The name Pirarucu comes from merging two Tupi words: Pirá (fish) and Urucum (red), due to their red tail, more visible on the males during mating season.

There's a local indigenous legend, in which Pirarucu was a brave warrior, son of a kind tribe chief, but unlike his father, he had a very selfish and proud nature. He mocked the gods and they tried to scare him with their powers so the guy would show them some respect, giving him a few chances, but he still didn't care and refused to respect them even after being struck by lightning, so as punishment, They dragged him down the river and turned him into a giant fish!

[fishenjoyer1]

Fish of the Day

Today's fish of the day is the pirarucu!

The pirarucu, scientific name Arapaima gigas, is known for its impressive size. Getting as large as 3 meters, and about 10ft in length, the pirarucu is one of the largest freshwater fish in the world! Living in the Amazon river basin, this fish can be found in Peru, Brazil, and Guyana, with an invasive population within Bolivia, and some Eastern Asian countries. It is thought that this fish washed into Bolivia in the mid 1970's when a nearby Peruvian fish farm was flooded, and since then the pirarucu has wreaked havoc among the local fish populations, although the populations introduced into Asia have far less issues. Within their range, these fish prefer to live in slower moving waters or stagnant areas of lakes, and have a breeding season tied to the water amount in local waterways.

The diet of the pirarucu is made up primarily of fish along the basin bed, but a secondary large section of their diet is made up of small insects and other invertebrates at the surface of the water, along with crustaceans and water birds. These fish are air breathers, and must travel to the surface every 10-20 minutes to swallow in a mouthful of air, in a loud gasp, during which time they also hunt for prey. These fish are predated on in their natural habitat by crocodiles, boto, and humans, and they have adapted defenses, the pirarucu has large bony armor spanning the length of the body, similar to that of  plecostomus fish.The lung structure that allows them to breath air is made out of a modified swim bladder that has adapted for easier gas exchange. 

During the drought months of February-April, the pirarucu will begin spawning, laying its eggs. Then after this during the flooding months, these eggs will hatch. For the first 8 days of their lives these fish survive off of a gill structure, before going through a morphology change as the gills adapt to ion absorption rather than water intake. These babies are then protected by the male and female pirarucu within a built nest for up to three months, during which time they can get as large as a 1ft. By it's first year of life, these fish can get as large as 3ft, and reach sexual maturity by their fifth year. Then, they can live as long as 10-20 years. Although we don't know exactly when these fish would have started existing within their family, within Columbia, a 13 million year old fossil of pirarucu, or an ancestor of was found.

That's the pirarucu, everybody. Have a wonderful day!

[colorsoutofearth]

Arapaima (Arapaima gigas) skin detail

Photos by Pete Oxford

[juliusllopis]

Arapaima of death.

Fineliners and Parker ink with water and bleach. Available.

ETSY

[littlemissy-juju]

Gotetober 2024 day 1 - Cannibalism

Pirarucu eatin Pirarucu 😇

[aquatark]

Pirarucu (Blue) - Veiled Sea

Endless Ocean Luminous, Nintendo Switch

this is one of my favourite rare color variants of a creature - it's so pretty looking!! i wish they were real...

[skovoxblitzer]

himb <3

[gaiakoraidon]

A while back one of my friends discovered and played a game called Goonya Monster, and she really enjoyed it. She recommended the game to me, and I decided to do some research into it. The game actually catches my interest and I have plans to buy and play it in the near future. The art style really does appeal to me; it's so cute! I decided to draw Pirarucu from the game since she stands out to me the most out of the four main protagonists meaning yeah out of the main four she's probably my favorite.

[martinogolter]

VagasLuzes

Acrylic paint & oil stick

On canvas

111x111cm

https://lnkd.in/dXkU-UZZ

#vagasluzes #painting #contemporaryart #artecontemporanea #contemporarypainting #martinogolter #pirarucu #ecology #ecologie #amazonia #brasil #abstractart #malerei #kunst #nature #grid #art #fishscales #fishleather #courodepirarucu #recycle #rioamazonas #para

[animemakeblog]

“City Hunter Movie: Tenshi no Namida” The Trailer

The opening theme, key visual, and trailer for the upcoming film City Hunter: Tenshi no Namida (City Hunter The Movie: Angel Dust) were all announced on the movie's official website. The movie is slated to premiere on September 8 in theatres.

[hst432]

ピラルク 須磨シーワールド スマコレクション

無料エリアで淡水巨大魚が見られるのはうれしい。

[revista-amazonia]

Aspectos históricos de ocupação do Sudeste do Pará

A evolução histórica do sudeste paraense teve origem em Conceição do Araguaia, a partir de um território desmembrado do município de Baião, que, inicialmente, era um Arraial e depois se tornou Freguesia em 14.04.1900. O crescimento acelerado da Freguesia fez com que o Poder Legislativo do Estado do Pará, por intermédio da Lei nº 1.905 de 18.10.1920, criasse o Município de Conceição do…