Characiformes is an order of ray-finned fish, comprising the characins and their allies. Grouped in 18 recognized families, more than 2000 different species are described, including the well-known piranha and tetras.
The Amazon basin is the part of South America drained by the Amazon River and its tributaries. The Amazon drainage basin covers an area of about 7,000,000 km2 (2,700,000 sq mi), or about 35.5 percent of the South American continent. It is located in the countries of Bolivia, Brazil, Colombia, Ecuador, Guyana, Peru, Suriname, and Venezuela, as well as the territory of French Guiana.
Batrachoididae is the only family in the ray-finned fish order Batrachoidiformes. Members of this family are usually called toadfish or frogfish: both the English common name and scientific name refer to their toad-like appearance.
Pterophyllum is a small genus of freshwater fish from the family Cichlidae known to most aquarists as angelfish. All Pterophyllum species originate from the Amazon Basin, Orinoco Basin and various rivers in the Guiana Shield in tropical South America. The three species of Pterophyllum are unusually shaped for cichlids being greatly laterally compressed, with round bodies and elongated triangular dorsal and anal fins. This body shape allows them to hide among roots and plants, often on a vertical surface. Naturally occurring angelfish are frequently striped transversely, colouration which provides additional camouflage. Angelfish are ambush predators and prey on small fish and macroinvertebrates. All Pterophyllum species form monogamous pairs. Eggs are generally laid on a submerged log or a flattened leaf. As is the case for other cichlids, brood care is highly developed.
The arapaima, pirarucu, or paiche is any large species of bonytongue in the genus Arapaima native to the Amazon and Essequibo basins of South America. Arapaima is the type genus of the subfamily Arapaiminae within the family Osteoglossidae. They are among the world's largest freshwater fish, reaching as much as 3 m (9.8 ft) in length. They are an important food fish. They have declined in the native range due to overfishing and habitat loss. In contrast, arapaima have been introduced to several tropical regions outside the native range, where they are sometimes considered invasive species. In Kerala, India, arapaima escaped from aquaculture ponds after floods in 2018. Its Portuguese name, pirarucu, derives from the Tupi language words pira and urucum, meaning "red fish".
Arapaima gigas, also known as pirarucu or simply arapaima, is a species of arapaima native to the basin of the Amazon River. Once believed to be the sole species in the genus, it is among the largest freshwater fish. The species is an obligate air breather, so it needs to come to the surface regularly to breathe air.
The clown loach, or tiger botia, is a tropical freshwater fish belonging to the botiid loach family. It is the sole member of the genus Chromobotia. It originates in inland waters in Indonesia on the islands of Sumatra and Borneo. In Sentarum, West Borneo that fish named: ulanguli. It is a popular fish in the freshwater aquarium trade and is sold worldwide.
Ostariophysi is the second-largest superorder of fish. Members of this superorder are called ostariophysians. This diverse group contains 10,758 species, about 28% of known fish species in the world and 68% of freshwater species, and are present on all continents except Antarctica. They have a number of common characteristics such as an alarm substance and a Weberian apparatus. Members of this group include fish important to people for food, sport, the aquarium industry, and research.
The tambaqui is a large species of freshwater fish in the family Serrasalmidae. It is native to tropical South America, but kept in aquaculture and introduced elsewhere. It is also known by the names black pacu, black-finned pacu, giant pacu, cachama, gamitana, and sometimes as pacu.
Santanichthys diasii is a species of extinct fish that existed around 115 million years ago during the Albian age. S. diasii is regarded as the basal-most characiform, and is the earliest known member of Otophysi. It appears as a small fish, similar in appearance to a modern-day herring little more than 30 millimeters in length. Its most striking characteristic is the presence of a Weberian apparatus, which makes it the most primitive known member of the order Characiformes, the order in which modern-day tetras are classified. Santanichthys has been unearthed from numerous locations throughout Brazil, in rocks dating to the Cretaceous Period. Its presence in these strata is seen as an indicator for the biogeography and evolution of its order.
Rhyacoschistura suber is a species of ray-finned fish, a stone loach, in the genus Rhyacoschistura. This species was originally described from three specimens collected among leaf litter in very shallow water in a small forest creek in the Nam Leuk drainage basin in Laos in 1997. These specimens were revealed to be juveniles and the species was re-described in 2019 on the basis of adult specimens. Based on the re-description, the species was moved from Schistura to the newly described genus, Rhyacoschistura.
Igapó is a word used in Brazil for blackwater-flooded forests in the Amazon biome. These forests and similar swamp forests are seasonally inundated with freshwater. They typically occur along the lower reaches of rivers and around freshwater lakes. Freshwater swamp forests are found in a range of climate zones, from boreal through temperate and subtropical to tropical. In the Amazon Basin of Brazil, a seasonally whitewater-flooded forest is known as a várzea, which is similar to igapó in many regards; the key difference between the two habitats is in the type of water that floods the forest.
Nannostomus anduzei is a freshwater species of fish belonging to the genus Nannostomus in the characin family Lebiasinidae. It is native to Venezuela and northern Brazil, particularly the upper Orinoco and Rio Ererê, a tributary of the Rio Negro. The adults grow to a maximum length of only 16 mm, making them one of the smallest pencilfish. Other common names include miniature pencilfish, miniature nannostomus, and Anduzi's nannostomus.
Vaillantella maassi, the forktail loach, is a species of loach in the family Vaillantellidae, a monogeneric family with two other species, Vaillantella cinnamomea and Vaillantella euepiptera. They are from Southeast Asia.
Leptophilypnion is a genus of tiny fishes in the family Eleotridae endemic to the Amazon Basin in South America. At less than 1 cm (0.4 in) in standard length they are the smallest sleeper gobies and among the smallest fish. The larger Microphilypnus sleeper gobies are also found in the Amazon, and sometimes occur together with Leptophilypnion. The bottom-dwelling Leptophilypnion are typically found in shallow, stagnant or slow-flowing water among soft debris, leaf-litter or water plants.
Microphilypnus is a genus of small fishes in the family Eleotridae native to the Amazon and Orinoco basins in South America. At up to 2.4 cm (0.94 in) in standard length, they are among the smallest sleeper gobies, but however larger than the Leptophilypnion sleeper gobies from the same region. The bottom-dwelling Microphilypnus are typically found in shallow water among leaf-litter or partially buried in sand, and they can be very abundant in their habitat. Their small size combined with a speckled and semi-transparent appearance makes them highly cryptic. They somewhat resemble certain freshwater shrimp, as well as Priocharax characins, and they sometimes group together. Microphilypnus feed on tiny invertebrates.
Synocrossus beauforti, the barred loach, chameleon loach or chameleon botia, is a species of freshwater fish from the loach family Botiidae which is found in mainland south-east Asia.
The tailspot tetra is a freshwater fish that lives in the coastal river regions of upper South America. Both its common and scientific names reference the distinct spot of color present on the tail fin, which is one of its defining characteristics. It is a small fish, reaching 4.8 in at its longest. Despite its small size, it is an active swimmer, with a preference for fast-flowing waters.
Bryconops giacopinii is a mid-sized species of freshwater fish in the family Iguanodectidae. It is the largest member of the genus Bryconops, and is therefore difficult to confuse with any of its congeners. With a diet that consists largely of land-dwelling insects, it serves as an important link between the terrestrial and aquatic aspects of its native range.
Iguanodectes spilurus, the green-line lizard tetra, is a small characiform fish from the rivers of South America. It is not a well-studied species, but research is available, including data from hobbyists that keep it as an ornamental fish. It has a distinct lateral stripe of reflective-green scales, and lacks any red markings therein; red is common in congeners' lateral stripes.
