Synbranchiformes, often called swamp eels, is an order of ray-finned fishes that are eel-like but have spiny rays, indicating that they belong to the superorder Acanthopterygii.
The swamp eels are a family (Synbranchidae) of freshwater eel-like fishes of the tropics and subtropics. Most species are able to breathe air and typically live in marshes, ponds and damp places, sometimes burying themselves in the mud if the water source dries up. They have various adaptations to suit this lifestyle; they are long and slender, they lack pectoral and pelvic fins, and their dorsal and anal fins are vestigial, making them limbless vertebrates. They lack scales and a swimbladder, and their gills open on the throat in a slit or pore. Oxygen can be absorbed through the lining of the mouth and pharynx, which is rich in blood vessels and acts as a "lung".
Channa is a genus of predatory fish in the family Channidae, commonly known as snakeheads, native to freshwater habitats in Asia. This genus contains about 50 scientifically described species. The genus has a wide natural distribution extending from Iraq in the west, to Indonesia and China in the east, and parts of Siberia in the Far East. A particularly high richness of species exists in Myanmar (Burma) and northeastern India, and many Channa species live nowhere else. In contrast, a few widespread species have been introduced to several regions outside their natural range, where they often become invasive. The large and medium-sized Channa species are among the most common staple food fish in several Asian countries, and they are extensively cultured. Apart from their importance as a food fish, snakeheads are consumed in some regions as a traditional medicine for wound healing and reducing postoperative pain and discomfort, and collected for the international aquarium pet trade.
Labeo is a genus of carps in the family Cyprinidae. They are found in freshwater habitats in the tropics and subtropics of Africa and Asia.
Mastacembelus is a genus of many species of spiny eel fish from the family Mastacembelidae. They are native to Africa and Asia. Most are found in rivers and associated systems, but there are also species in other freshwater habitats and a particularly rich radiation is found in the Lake Tanganyika basin with 15 species. A few species can even occur in brackish water.
Garra is a genus of fish in the family Cyprinidae. These fish are one example of the "log suckers", sucker-mouthed barbs and other cyprinids commonly kept in aquaria to keep down algae. The doctor fish of Anatolia and the Middle East belongs in this genus. The majority of the more than 140 species of garras are native to Asia, but about one-fifth of the species are from Africa.
The Liberian swamp eel is a species of fish in the family Synbranchidae. It is indigenous to Liberia. It has also been found in Sierra Leone, with an unconfirmed report from Côte d'Ivoire. It was first described by Jacques Pellegrin in 1922 as Typhlosynbranchus boueti, but was later moved to Monopterus. However, a 2020 study revived Typhlosynbranchus. Due to the deficiency in data, the species has not been classified with respect to endangerment.
Monopterus is a genus of swamp eels native to Asia. They live in various freshwater habitats and some have a fossorial lifestyle.
The Bombay swamp eel, also known as the paytop in Marathi, is a species of fish in the family Synbranchidae. It is endemic to the state of Maharashtra in India.
The Asian swamp eel, also known as rice eel, ricefield eel, rice paddy eel or white rice-field eel, is a commercially important, air-breathing species of fish in the family Synbranchidae. It occurs in East and Southeast Asia, where it is a very common foodstuff sold throughout the region. It has been introduced to two areas near the Everglades in Florida and near Atlanta in Georgia.
The Garo spineless eel, Garo khajuriai, is a species of earthworm eel endemic to India. It belongs to the monotypic genus Garo. It is demersal and lives in fresh water
Indostomus is a genus of small fishes native to slow moving or stagnant freshwater habitats in Indochina. It is the sole genus of the monogeneric family Indostomidae, Long considered to be sticklebacks, within the order Gasterosteiformes, modern analyses place the Indostomids within the order Synbranchiformes, related to the spiny eels and swamp eels.
Loaches are fish of the superfamily Cobitoidea. They are freshwater, benthic (bottom-dwelling) fish found in rivers and creeks throughout Eurasia and northern Africa. Loaches are among the most diverse groups of fish; the 1249 known species of Cobitoidea comprise about 107 genera divided among 9 families.
Badis is a genus of freshwater fish in the family Badidae found in South Asia, Southeast Asia and China. These species have a sharp spine on the opercle, soft and spinous parts of the dorsal fin contiguous, three spines in the anal fin, tubed pores in the lateral line, villiform teeth and a rounded caudal fin. In addition, they differ from the related genus Dario by being larger and displaying more involved parental care.
Ophichthys desilvai is a commercially important, air-breathing species of fish in the family Synbranchidae. It is endemic to Sri Lanka and is the only endemic synbranchid from there.
Rakthamichthys rongsaw is a species of swamp eel discovered in the Khasi Hills in northeast India. The researchers were searching for caecilians, when they uncovered the eel in soil.
Synbranchinae is a subfamily of swamp eel, consisting of six of the ten genera in the family Synbranchidae. The remaining genus, the monotypic Macrotrema is the only one in the other subfamily Macrotreminae. The subfamily occurs in the Neotropics, Afrotropics and Asia.
Rakthamichthys is a genus of swamp eels that are endemic to India. Three species are known from the Western Ghats and one is known from Northeast India.
The Malabar swamp eel is a species of troglobitic swamp eel endemic to subterranean springs in Kottayam in the Indian state of Kerala.
Ophichthys is a genus of swamp eels native to South Asia. They live in freshwater or subterranean habitats, and some have a fossorial lifestyle.
