Ancistrus is a genus of nocturnal freshwater fish in the familyLoricariidae of order Siluriformes, native to freshwater habitats in South America and Panama. Fish of this genus are common in the aquarium trade where they are known as bushynose or bristlenose catfish. In the aquarium hobby they are often referred to as bushynose or bristlenose plecos instead, but this may lead to confusion as "pleco" usually is used for Hypostomus plecostomus and its allies and is often used as a catchall term for any loricariids remotely resembling that species.
The name ancistrus derives from the Ancient Greekagkistron "hook"– a reference to the form of the cheek odontodes. The genera Pristiancistrus, Thysanocara and Xenocara are now synonyms of Ancistrus.[2]
Description
Ancistrus cirrhosusAncistrus sp.
Ancistrus species show all the typical features of the Loricariidae. This includes a body covered in bony plates and a ventral suckermouth.[3] The feature most commonly associated with the genus are the fleshy tentacles found on the head in adult males; females may possess tentacles along the snout margin but they are smaller and they lack tentacles on the head.[3]Tentacules, tentacles directly associated with odontodes, develop on the pectoral fin spine of the males of some species.[3] Males also have evertible cheek odontodes which are less developed or absent in females. They also lack odontodes along the snout.[2] In comparison with a typical loricariid (pleco), a bristlenose is typically shorter (4–6 inches or 15cm or less), more flattened and fatter with a comparatively wider head. Colouration is typically mottled brown, grey or black. Small white or yellow spots are common.[2] In contrast to many other loricariid 'plecos' (many of which regularly exceed a foot in captivity), the bristlenose plecos do not usually exceed six inches in length; they can thus be kept in relatively small tanks, contributing to their popularity in the aquarium hobby.
Ancistrus species are unusual among vertebrates in possessing an X0 sex-determination system, which is the prevailing method in many lineages of arthropod but is very rare elsewhere in the animal kingdom.[4]
Distribution and habitat
Ancistrus is one of the widest ranging Loricariid genera, and representatives are found in most areas where the family in general is present.[2] Many species are found in the rivers and floodplain areas of the Amazon basin, but there are also species elsewhere in tropical South America, as well as species on the island of Trinidad and two species, A.centrolepis and A.chagresi in Panama.[5] Three species are true cavefish (troglobites): A.cryptophthalmus, A.galani and A.formoso.[6][7] These are the only known loricariids that possess adaptions for a subterranean lifestyle, such as reduced pigmentation (appearing overall whitish) and eyes.[6]
Aquarium maintenance
In the wild, Ancistrus species prefer flowing water, so tanks with flow are typically used when keeping them in captivity. Since they are bottom-dwelling fish, substrate is considered preferable to a bare tank floor. Mixtures of gravel, dirt, and clay are frequently used as substrate for Ancistrus.
The aquarium size that is considered by some to be a minimum for fish of this genus is 25 gallons.[8][self-published source?]
Species
There are currently 76 recognized species in this genus:[9]
Albino bristlenose catfish are common in the aquarium trade.
The diet of this genus is typical for a Loricariid– algae, aufwuchs, and detritus, with sediment, sand, and gravel presumably ingested accidentally alongside food items.[13][14][15][16][17][18] Despite reports among fish-keepers that they require wood in their diet, no scientific evidence to date supports members of this genus feeding on wood. Bristlenoses do not school but hide when not feeding, juveniles however are typically found in brightly lit shallows at the water margin making them susceptible to predation by birds.
Ancistrus species have the capability of obtaining oxygen through their modified stomach.[19] This allows them to survive in conditions with low oxygen levels.[2]
Breeding takes place in hollows, caves and mud holes in banks. Males may clean the inside of the cavity with their suckermouth before allowing the female to approach and inspect the nest. Courtship includes expanding the dorsal and caudal fins and attempts by the male to escort the female to the nest. While the female inspects the nest, the male keeps close contact.[3] The female may lay 20–200 adhesive eggs, usually to the ceiling of the cavity.[3]
The female plays no role in parental care; the male takes care of its young. Males will clean the eggs and the cavity with its fins and mouth. Males inspect eggs to remove diseased or infertile eggs, and aerates the clutch by fanning them with its pectoral and pelvic fins.[3] During this time, a male usually will not leave the cavity to feed, or will leave only occasionally and quickly return.[3] The eggs hatch in 4–10 days over a period of 2–6 hours; the male guards the eggs for 7–10 days after hatching.[3] The fry remain in the cave, attaching to the walls and ceiling with their mouths, absorbing their yolk sac in 2–4 days and becoming free swimming.[3]
Males of these species are competitive and territorial. Males display to each other by positioning themselves parallel to each other, head to tail, with dorsal and caudal fins erect and cheek odontode spines everted. If this escalates to combat, the males will circle each other and direct attacks at the head.[3] If an intruding male manages to evict another male from the nest, it may cannibalize the other male's young.[3]
A male bristlenose may guard several clutches of eggs simultaneously. Females prefer males that are already protecting eggs and may prefer males that are protecting larvae; it has been suggested that the tentacles may act as a fry mimic to attract females, which would allow males without eggs in their nest to compete with males guarding eggs.[3] Several clutches in various states of development from eggs to free-swimming larvae can be found in one nest.[2]
In the aquarium
Female Ancistrus sp. on a piece of cucumber
These fish are often kept by aquarists, as they are dutiful algae-eaters and smaller in adult size than the common plecos usually seen in pet shops. They reach up to 15cm (5.9in) in males, and 12cm (4.7in) in females. Their recommended temperature is 23–27°C (73–81°F). Their lifespan is up to 12 years. They are hardy animals, tolerant to a wide range of water conditions. They breed easily in captivity, and are compatible with most other freshwater fish. Though typically mottled brown or black-and-grey spotted in color, other species are more exotic– spots of bright yellow on a dark background being a common pattern. Albino variants are also common. The albino morph is not caused by exposure to light during development, it is a morph controlled by genetics.[20]
Historically, commonly available species of Ancistrus were Ancistrus cirrhosus and Ancistrus temminckii; other species are now available, though exact identification is difficult.
Feeding is easy, bristlenoses will graze on algae/ algae wafers and other surface growing organisms as well as eating algae wafers or tablets, flake food, squash, spinach, cucumber, zucchini, green beans peas and even sliced carrots. They have also been known to accept frozen bloodworms as part of their diet. Aquarium specimens may starve for lack of algae or other plant matter; algae wafers or other low-protein foods are recommended. Keepers should watch for the abdomen to take on a sunken appearance, indicating insufficient nutrition.
Sexing is very easy as the female will only occasionally have bristles, around the edge of the chin, whereas the male will have them up the center of the head.
Breeding is also possible. Males attract females to a small cave or hollow, then guard eggs after fertilization through hatching (4–8 days) until fry are free swimming (4–6 days after hatching); the aquarist need only supply a suitable cave, food, and one of each sex.
Caution should be taken with the spines (odontodes); although the risk of personal injury is small with this genus, the hooked nature of the odontodes means that a bristlenose may become trapped in non-natural material such as sponge filters and netting.
Loricariidae is the largest family of catfish, with 92 genera and just over 680 species. Loricariids originate from freshwater habitats of Costa Rica, Panama, and tropical and subtropical South America. These fish are noted for the bony plates covering their bodies and their suckermouths. Several genera are sold as "plecos", notably the suckermouth catfish, Hypostomus plecostomus, and are popular as aquarium fish.
Hypostomus is a genus of catfish in the family Loricariidae. They are native to tropical and subtropical South America. H. plecostomus is the popular freshwater aquarium fish formerly known as Plecostomus plecostomus. The taxonomic structure of the Loricariidae is still being expanded by scientists. Hypostomus is a highly species-rich and widely distributed catfish genus.
Otocinclus is a genus of catfish in the family Loricariidae native to South America, commonly known as "dwarf suckers" or "otos". This genus, like other loricariids, is characterized by rows of armour plating covering the body, as well as the underslung suckermouth. They are generally small in size; O. tapirape is the smallest of the species (2.4 cm), while O. flexilis is the biggest (5.5 cm). These species have adaptations that allow them to breathe air. A duct forms at the junction between the esophagus and the stomach and expands into an enlarged, ring-like diverticulum, characteristic of this genus, which allows air-breathing. Otocinclus are popular aquarium fish, and they are often purchased as algae eaters. It is difficult to breed them in captivity, and only wild caught Otocinclus are available to hobbyists. This genus is widely distributed east of the Andes of South America, throughout the lowlands from northern Venezuela to northern Argentina, but are generally absent from the Amazon and the Orinoco lowlands.
The genus Panaque contains a small number of small to medium-sized South American suckermouth armoured catfishes that are notable for being among the very few vertebrates that feed extensively on wood. In addition, algae and aufwuchs are an important part of the diet, and they use their rasping teeth to scrape this from rocks. These fish are also popular aquarium fish, where the sound of scraping as these fish forage for food is easily audible.
Pterygoplichthys, sometimes collectively known as janitor fish, is a genus of South American armored catfishes. These fish are commonly known as sailfin armoured catfish or sailfin plecs, especially in the aquarium trade.
Baryancistrus is a genus of freshwater Loricariid catfish. They inhabit flowing sections of rivers, especially clearwater, in the basins of the Amazon and Orinoco in Brazil and Venezuela. The largest species reach up to 34 cm (13 in) in total length.
Pseudancistrus is a genus of suckermouth armored catfishes native to South America.
Rineloricaria is a genus of freshwater tropical catfish belonging to the family Loricariidae. They are commonly called whiptail catfish because of the long filament that grows out of the tip of the caudal fin that is characteristic of the genus. With the exception of R. altipinnis from Panama, they are native to the rivers of northern and central South America. Some species are regularly seen in the aquarium trade.
Hypancistrus is a genus of loricariid catfish originating from the Amazon basin in South America. Unlike many of the other Loricariids, however, some Hypancistrus species are more carnivorous and enjoy meat in their diet. Hypancistrus species are popular aquarium fish, including such popular fish as the zebra pleco and Queen Arabesque pleco.
Peckoltia is a genus of small South American armored suckermouth catfishes. Many of these fish are popular aquarium fish.
Hemiancistrus is a genus of suckermouth armored catfishes. These species are native to South America. The taxonomy of this genus is complex and unclear, and major work has to be done. Many of these fish are popular aquarium fish.
Loricariinae is a subfamily of the family Loricariidae of catfish. This subfamily is divided into two tribes and about 30 genera. They are mainly native to freshwater habitats in South America, but there are also several species in Panama and a single (Fonchiiichthys) in Costa Rica.
Loricariichthys is a genus of catfishes of the family Loricariidae.
Harttia is a genus of armored catfishes native to South America.
Loricaria is a genus of armored catfish native to South America.
Ancistrini is a tribe of catfishes of the family Loricariidae. Most are restricted to tropical and subtropical South America, but there are also several genus in southern Central America.
Neoplecostomus is a genus of fish in the family Loricariidae native to South America. Neoplecostomus can be distinguished from all other loricariids by a modified shield of small plates on the abdomen with posteriorly directed odontodes; the shield appears to act as a holdfast. The color pattern is generally mottled brown with the abdomen white. The head is long, rounded, and shovel-shaped. The fin spines are weak. They range from about 8 to 11 cm (3.1–4.3 in) SL. The species of Neoplecostomus live in fast-flowing water.
Paralithoxus is a genus of suckermouth armored catfishes native to tropical South America.
Pseudolithoxus is a genus of suckermouth armored catfishes with five described species from the basins of the Orinoco, Casiquiare and upper Rio Negro in Venezuela. Additionally, a possibly undescribed species is known from the Trombetas and Nhamundá rivers in Brazil.
'Pseudancistrus' megacephalus is a species of catfish in the family Loricariidae. It is of uncertain and disputed classification.
↑ Anderson, Luís Alves; Oliveira, Claudio; Nirchio, Mauro; Granado, Ángel and Foresti, Fausto; 'Karyotypic relationships among the tribes of Hypostominae (Siluriformes: Loricariidae) with description of XO sex chromosome system in a Neotropical fish species'; Genetica, vol. 128 (2006); pp. 1–9
1 2 Romero, A. (2001): The Biology of Hypogean Fishes. Developments in Environmental Biology of Fishes. ISBN978-1-4020-0076-8
↑ Trajano, E. (2001). "Habitat and Population Data of Troglobitic Armored Cave Catfish, Ancistrus cryptophthalmus Reis, 1987, from Central Brazil (Siluriformes: Loricariidae)". Environmental Biology of Fishes. 62 (1): 195–200. doi:10.1023/A:1011884829498. S2CID22106285.
1 2 3 Lujan, N.K., Meza-Vargas, V., Astudillo-Clavijo, V., Barriga-Salazar, R. & López-Fernández, H. (2015): A Multilocus Molecular Phylogeny for Chaetostoma Clade Genera and Species with a Review of Chaetostoma (Siluriformes: Loricariidae) from the Central Andes. Copeia, 103 (3): 664-701.
1 2 de Oliveira, R.R., Rapp Py-Daniel, L., Zawadzki, C.H. & Zuanon, J. (2016): Two new Amazonian species of Ancistrus with vestigial adipose fin, with an appraisal on adipose fin loss in neotropical armoured catfishes (Teleostei: Loricariidae). Ichthyological Exploration of Freshwaters, 27 (1): 67-80.
↑ de Oliveira, R.R., Zuanon, J., Zawadzki, C.H. & Rapp Py-Daniel, L. (2015): Ancistrus maximus, a new species of red-dotted armored catfish from rio Branco, Roraima State, Brazilian Amazon (Siluriformes: Loricariidae). Ichthyological Exploration of Freshwaters, 26 (1): 73-82.
↑ Kramer, Donald L.; Bryant, Michael J. (February 1, 1995). "Intestine length in the fishes of a tropical stream: 2. Relationships to diet — the long and short of a convoluted issue". Environmental Biology of Fishes. 42 (2): 129–141. doi:10.1007/BF00001991. S2CID33113299– via Springer Link.
↑ Power, Mary E. (April 1, 1984). "The importance of sediment in the grazing ecology and size class interactions of an armored catfish, Ancistrus spinosus". Environmental Biology of Fishes. 10 (3): 173–181. doi:10.1007/BF00001124. S2CID13343092– via Springer Link.
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