Leiarius
Encyclopedia
Leiarius is a genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of catfish
Catfish
Catfishes are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the heaviest and longest, the Mekong giant catfish from Southeast Asia and the second longest, the wels catfish of Eurasia, to detritivores...

es (order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...

 Siluriformes) of the family
Family
In human context, a family is a group of people affiliated by consanguinity, affinity, or co-residence. In most societies it is the principal institution for the socialization of children...

 Pimelodidae
Pimelodidae
Pimelodidae, commonly known as the long-whiskered catfishes, is a family of catfishes .-Taxonomy:Pimelodidae has undergone much revision. Currently, the family contains about 30 genera and about 90 recognized and known but unnamed species...

. It includes four species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

. Most of the genus' species are ornamental species kept as pets in the aquarium
Aquarium
An aquarium is a vivarium consisting of at least one transparent side in which water-dwelling plants or animals are kept. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, marine mammals, turtles, and aquatic plants...

 hobby
Hobby
A hobby is a regular activity or interest that is undertaken for pleasure, typically done during one's leisure time.- Etymology :A hobby horse is a wooden or wickerwork toy made to be ridden just like a real horse...

.

Taxonomy

There are four species attributed to the genus Leiarius: L. marmoratus, L. arekaima, L. longibarbis and L. pictus. However, at least one source considers L. arekaima and L. longibarbis species inquirendae of the genus.

Anatomy and physiology

L. marmoratus can reach a little more than 100 centimetre
Centimetre
A centimetre is a unit of length in the metric system, equal to one hundredth of a metre, which is the SI base unit of length. Centi is the SI prefix for a factor of . Hence a centimetre can be written as or — meaning or respectively...

s (39 in
Inch
An inch is the name of a unit of length in a number of different systems, including Imperial units, and United States customary units. There are 36 inches in a yard and 12 inches in a foot...

) TL
Fish measurement
Fish measurement refers to the measuring of the length of individual fish and of various parts of their anatomy. These data are used in many areas of ichthyology, including taxonomy and fisheries biology.-Overall length:...

 and has a maximum published weight of about 12 kilogram
Kilogram
The kilogram or kilogramme , also known as the kilo, is the base unit of mass in the International System of Units and is defined as being equal to the mass of the International Prototype Kilogram , which is almost exactly equal to the mass of one liter of water...

s (26 lb
Pound (mass)
The pound or pound-mass is a unit of mass used in the Imperial, United States customary and other systems of measurement...

). L. pictus grows to 60 cm (24 in) TL.

These two species can be easily confused. The body of L. pictus is brown with darker brown spots, with a paler ventral coloring. In juvenile L. pictus, two parallel, pale bands curve from the dorsal fin
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...

 down the body towards the caudal fin. In young fish of both species, the maxillary barbels
Barbel (anatomy)
A barbel on a fish is a slender, whiskerlike tactile organ near the mouth. Fish that have barbels include the catfish, the carp, the goatfish, sturgeon, the zebrafish and some species of shark...

 are very long and ringed with black and white. As both of these species grow, their barbels will shorten in proportion to their size, and the caudal fin lobes, which are rounded in the young, become much more pointed. As L. marmoratus grows older, it darkens and its dark spots develop into a marbled pattern. Both species have a large, sail-like dorsal fin.

There are no external sexual differences.

Range and distribution

L. marmoratus is found in the Amazon
Amazon River
The Amazon of South America is the second longest river in the world and by far the largest by waterflow with an average discharge greater than the next seven largest rivers combined...

, Essequibo
Essequibo River
The Esequibo River is the largest river in Guyana, and the largest river between the Orinoco and Amazon. Rising in the Acarai Mountains near the Brazil-Guyana border, the Essequibo flows to the north for 1,010 km through forest and savanna into the Atlantic Ocean.-Geography:There are countless...

, and Orinoco River basins. On the other hand, L. pictus is only found in the Amazon and Orinoco River basins.

Ecology

L. marmoratus inhabits riverbeds, deep wells, and lakes. Young or sub-adults form large schools. This species prefers to lay over rock and tree trunks during the day, being more active at sunrise, sunset, and night.

In aquaria

Both L. marmoratus and L. pictus are ornamental fish kept as pets in the aquarium
Aquarium
An aquarium is a vivarium consisting of at least one transparent side in which water-dwelling plants or animals are kept. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, marine mammals, turtles, and aquatic plants...

 hobby
Hobby
A hobby is a regular activity or interest that is undertaken for pleasure, typically done during one's leisure time.- Etymology :A hobby horse is a wooden or wickerwork toy made to be ridden just like a real horse...

. They have a voracious appetite and can grow rapidly, and therefore should be kept in a very large aquarium. These fish are peaceful towards other large fish. Some sort of retreat to allow these fish to hide during the day is required. These fish get very large and are not recommended for the average aquarist.
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