''Serrasalmus geryi'', known as the violet line piranha or Gery's piranha, is a species of

piranha A piranha (, or ; ) is any of a number of freshwater fish species in the subfamily Serrasalminae, of the family Serrasalmidae, in the order Characiformes. These fish inhabit South American rivers, floodplains, lakes and reservoirs. Although ...

of the family

Serrasalmidae The Serrasalmidae (serrasalmids) are a family of characiform fishes native to freshwater habitats of South America. They include more than 90 species. The name means "serrated salmon family", which refers to the serrated keel running along the ...

. It is found in the lower

Tocantins Tocantins () is one of the 26 states of Brazil. It is the newest state, formed in 1988 and encompassing what had formerly been the northern two-fifths of the state of Goiás. Tocantins covers and had an estimated population of 1,496,880 in 2014 ...

and Araguaia Rivers of

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

. The species is notable for being the one of only the members of the

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

Serrasalmus ''Serrasalmus'' is a genus of piranhas. They are collectively known as pirambebas; the "typical" piranhas like the piraya piranha are nowadays placed in '' Pygocentrus''. Like all piranhas, ''Serrasalmus'' are native to South America. These fis ...

'' that can coexist with others of the same species in captivity, however caution is advised. Gery's Piranha reaches sizes up to 12 inches in length. As of 2018, it is classified as

Least Concern A least-concern species is a species that has been evaluated and categorized by the International Union for Conservation of Nature (IUCN) as not being a focus of wildlife conservation because the specific species is still plentiful in the wil ...

by the

International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the stat ...

Description

The body shape of ''Serrasalmus geryi'' is very laterally compressed, similar to other ''

'' genus members '' S. altuvei'', '' S. hastatus'', '' S. compressus'' and '' S. altispinis''. The fish is distinctive at all ages, possessing a broad dark stripe running from the lower mouth to the top of the beginning of the

dorsal fin A dorsal fin is a fin on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found ...

. ''S. geryi'' does not exhibit

sexual dimorphism Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...

. The body is silver with numerous small spots on the flanks. The

anal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported o ...

hyaline A hyaline substance is one with a glassy appearance. The word is derived from , and . Histopathology Hyaline cartilage is named after its glassy appearance on fresh gross pathology. On light microscopy of H&E stained slides, the extracellula ...

with a broad black margin. The

pectoral Pectoral may refer to: * The chest region and anything relating to it. * Pectoral cross, a cross worn on the chest * a decorative, usually jeweled version of a gorget * Pectoral (Ancient Egypt), a type of jewelry worn in ancient Egypt * Pectora ...

and

ventral fin Pelvic fins or ventral fins are paired fins located on the ventral (belly) surface of fish, and are the lower of the only two sets of paired fins (the other being the laterally positioned pectoral fins). The pelvic fins are homologous to the hind ...

s are clear. A

humeral spot Humeral spot (from Latin ''humerus'', pertaining to the shoulder) is a mark or pattern found on several species of fish, typically above the pectoral fin. In insects, the humeral spot may be found on the Glossary_of_entomology_terms#Costa, cost ...

may be present. Eyes silvery to reddish-orange. Mature individuals reach a length of 25 cm (10 inches), with specimens rarely longer than 20 cm (8 inches) in captivity.

Care

Tank requirements: * Recommended tank sizes: 120x45x50 cm (48x18x20 in) for an adult specimen, minimum 60x30x30 cm (24x12x12 in) for a juvenile specimen, and minimum 150x50x60 cm (60x20x24 in) for multiple individuals. * Plants,

driftwood Driftwood is a wood that has been washed onto a shore or beach of a sea, lake, or river by the action of winds, tides or waves. It is part of beach wrack. In some waterfront areas, driftwood is a major nuisance. However, the driftwood provides ...

or rocks provide hiding places; the tank lights should be dimmed. * Heavy filtration is required to deal with the large amounts of waste this fish produces. * A powerhead can be added to provide currents. * Fish can be dangerous to hands and other extremities. Care is required in handling. Water temperature: * 24-29 degrees

Celsius The degree Celsius is the unit of temperature on the Celsius temperature scale "Celsius temperature scale, also called centigrade temperature scale, scale based on 0 ° for the melting point of water and 100 ° for the boiling point ...

(76-84 degrees

Fahrenheit The Fahrenheit scale () is a scale of temperature, temperature scale based on one proposed in 1724 by the German-Polish physicist Daniel Gabriel Fahrenheit (1686–1736). It uses the degree Fahrenheit (symbol: °F) as the unit. Several accou ...

). Water chemistry: * pH should be between 6.0 - 8.0, ideal is slightly acidic to neutral water: pH 6.5 - 7.2. Soft water is preferred. Compatible species: * ''S. geryi'' is one of the few ''Serrasalmus'' species that have successfully been kept in a group. However, it is highly recommended to keep Gery's Piranha as a solitary fish, as it remains a

parasitic Parasitism is a close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The ent ...

and highly aggressive species. If multiple individuals of this species are kept together, it should only be attempted by highly experienced piranha keepers who know exactly what they are doing, and know what risks are involved. Breeding: * No instances of captive breeding have been reported yet. Diet: * Fish (whole, fillet or feeders),

shrimp A shrimp (: shrimp (American English, US) or shrimps (British English, UK)) is a crustacean with an elongated body and a primarily Aquatic locomotion, swimming mode of locomotion – typically Decapods belonging to the Caridea or Dendrobranchi ...

cockles Cockle may refer to: * Cockle (bivalve), an edible, marine bivalve mollusc * ''Lolium temulentum'' (also cockle), an annual plant of the family Poaceae * Berwick cockle, a white-coloured sweet with red stripes * ''Cockle'', a codename for the fo ...

mussels Mussel () is the common name used for members of several families of bivalve molluscs, from saltwater and freshwater habitats. These groups have in common a shell whose outline is elongated and asymmetrical compared with other edible clams, whic ...

squid A squid (: squid) is a mollusc with an elongated soft body, large eyes, eight cephalopod limb, arms, and two tentacles in the orders Myopsida, Oegopsida, and Bathyteuthida (though many other molluscs within the broader Neocoleoidea are also ...

insects Insects (from Latin ') are hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs of jointed ...

earthworms An earthworm is a soil-dwelling terrestrial animal, terrestrial invertebrate that belongs to the phylum Annelida. The term is the common name for the largest members of the class (biology), class (or subclass (biology), subclass, depending on ...

, pellets. * Food items such as

poultry Poultry () are domesticated birds kept by humans for the purpose of harvesting animal products such as meat, Eggs as food, eggs or feathers. The practice of animal husbandry, raising poultry is known as poultry farming. These birds are most typ ...

mammal A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...

meat, and organ meat should be fed sparingly: once or twice a month at most. Meat needs to be unseasoned and trimmed of any fat. * On rare occasions, this species accepts vegetables, nuts, seeds, or fruit as well. * Live fish need to be quarantined first, so they are safe to feed (containing no diseases or parasites). *

Goldfish The goldfish (''Carassius auratus'') is a freshwater fish in the family Cyprinidae of the order Cypriniformes. It is commonly kept as a pet in indoor aquariums, and is one of the most popular aquarium fish. Goldfish released into the w ...

minnows Minnow is the common name for a number of species of small freshwater fish, belonging to several genera of the family Cyprinidae and in particular the subfamily Leuciscinae. They are also known in Ireland as pinkeens. While the common name can ...

and other members of the

Cyprinid Cyprinidae is a Family (biology), family of freshwater fish commonly called the carp or minnow family, including the carps, the true minnows, and their relatives the barb (fish), barbs and barbel (fish), barbels, among others. Cyprinidae is the ...

family (Carp-like fish) should be avoided, as these fish contain growth-inhibiting hormones (Thaiminase/Vitamin B1 inhibitors) that could negatively affect the piranha's health and development.

References

External links

"Serrasalmus geryi"
on

FishBase FishBase is a global species database of fish species (specifically finfish). It is the largest and most extensively accessed online database on adult finfish on the web.

{{Taxonbar, from=Q148813 Serrasalmidae Piranhas Fish of the Tocantins River basin Fish described in 1988