Redtail catfish, pirarara

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Onglets

Description

Distinguishing features

Known as the pirarara in Brazil, the redtail catfish has a large head and wide mouth that bears three pairs of long barbels (two pairs below the mouth and one above). Its eyes are relatively small.

The redtailed catfish has several colour variations. The specimens presented at the Biodome have a brownish back, covered with small dark-grey spots with a long white lateral band that runs from the tail all the way to the throat. Its belly is black and its caudal fin is red or orange, from which the fish derives its name. The other fins are also reddish but only at their extremities. The pectoral fins bear spines.

Unlike the majority of fish, the redtail catfish does not have scales. Rather its viscous body is covered with bony plates.

The redtail catfish can become very large.

Reproduction

There is very little information available about redtail catfish reproduction and to date only a single spawning event has been observed in captivity. It has been noted that females become more active just prior to reproduction and take on a more bright coloration, most notable on the tail, which turns a bright scarlet red.

During spawning a female will release hundreds (normally about 200) eggs that are copper coloured and measure about 6mm.

Diet

The redtail catfish is a powerful opportunistic predator. Its wide mouth allows it to swallow very large prey. Its diet is quite varied (omnivore). It feeds on seeds, fruits fallen from palms or other trees, crabs and other invertebrates as well as dead or living fish.

The redtail catfish is a slow-moving bottom-dweller. It lives and feeds on the bottom from where it is able to ambush its prey. It also uses its barbels to search for food buried in the sediment. These barbels are highly sensitive and armed with thousands of chemoreceptive cells that act as a sensory organ for detecting odours.

Predators

Young redtail catfish fall prey to piscivours birds and carnivorous fish

In the past, while this fish was occasionally caught, it was not eaten. Traditionally Amazonian fishermen would abide by certain superstitions that prohibit eating fish with dark coloured flesh. However, today in Brazil the fishery for redtail catfish is regulated and it is now eaten by both indigenous and non-indigenous peoples.

Habitat

The redtailed catfish is native to the Amazon, Orinoco (Venezuela) and Essequibo (Guyana) rivers. It frequents the freshwaters of streams, lakes and ponds.

It has also been introduced to Florida, Nebraska, Missouri, Tennessee and Texas. Sightings of this species in the United States are likely the result of aquarium hobbyists having released fish onto the wild.

The redtail catfish is calm and solitary. It likes to spend its time at the bottom of waterbodies hidden in holes, in between rocks and logs or beneath dense vegetation. Where water is particularly murky, the simplest of hiding places will suffice.

Ecology, behaviour

The redtail catfish is territorial and will fend off its congeners and even other fish species that belong to the same family, the Pimelodidae. The redtail catfish is a nocturnal species and prefers temperatures oscillating between 24°C and 29°C. It can tolerate a pH range between 5 and 9.

This species of catfish is well adapted to living in oxygen-poor waters. When oxygen becomes scarce, the redtail catfish becomes less active and begins to pump water through its gills. In extreme conditions it will simply come to breath at the surface of the water, where oxygen is more abundant.

The redtail catfish has very poor eyesight. Rather, it tends to follow the chemical trails left behind by its prey and can even detect electric fields. A little-known fact is that redtail catfish actually shed their skin much like snakes. During their molt the chemoreceptors become inactive preventing them from detecting their prey and they are therefore unable to feed.

The Brazilians of the Amazon often capture this fish for its skin, which is treated and transformed into a type of leather used for making a variety of items. It is said that this leather is very soft, supple and flexible but also very strong.

French name

Poisson-chat à queue rouge, pirarara

Scientific name

Phractocephalus hemioliopterus

Phylum

Chordata

Class

Osteichthyes (bony fish)

Order

Siluriformes

Family

Pimelodidae

Size

Length: 90 to 130 cm

Weight

Average: 45 kg, sometimes up to 80 kg

Life span

Possibly up to 100 years

Status

Common species, commercially exploited for sale to aquarists. Not evaluated by the IUCN.

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