Leptocephalus is a genus that was used for species of larval eels, called leptocephali, that were thought to be new fish species, or whose adult eel species were not known. Leptocephali differ so much in appearance from their adults that the larvae and adults of eels are not easily matched, and when first discovered, leptocephali were thought to be a distinct type of fishes, but not eels. Because of this, the genus designation of Leptocephalus was used for a while for unidentified leptocephali even after it was known that these were the larvae of eels thus becoming a "wastebasket taxon", but this practice is no longer used. Examples of marine congrid larvae, found in the western Indian Ocean and the Red Sea that were named this way are listed below. Only two species in two families are currently treated as having any validity, though the validity of L. bellottii is strongly in doubt.
Neoconger is a genus of eels of marine ray-finned fishes belonging to the family Moringuidae, the spaghetti eels. These eels occur in shallow tropical and subtropical waters.
The rusty spaghetti eel, also known as the rusty worm eel, the slender worm eel, or the intermediate thrush-eel is an eel in the family Moringuidae. It was described by Richard Bliss Jr. in 1883. It is a tropical, marine eel which is known from the Indo-Pacific region, including East Africa, Easter Island, the Ryukyu Islands, Australia, and Micronesia. It leads a benthic lifestyle, burrowing into sandy regions in reefs at a depth range of 1–40 m. Males can reach a maximum total length of 140 cm.
The Java spaghetti eel, also known as the Java thrush-eel, Java worm eel, and the black-tailed thrush eel is an eel in the family Moringuidae. It was described by Johann Jakob Kaup in 1856, originally under the genus Aphthalmichthys. It is a tropical, marine eel which is known from the Indo-Pacific, including East Africa, the Tuamoto Islands, the Ryukyu Islands, and Micronesia. It is a burrowing species which inhabits reefs at a depth range of 2–15 m. Males can reach a maximum total length of 120 cm.
The ridged eel is an eel in the family Moringuidae. It was described by Charles Frédéric Girard in 1858. It is a subtropical, marine eel known from the western Atlantic Ocean, including the northwestern Gulf of Mexico, Cuba, and northern South America. The larvae have been found ranging from the Straits of Florida to Brazil. It typically dwells at a depth range of 13–180 m, and inhabits offshore banks. Males can reach a maximum total length of 30 cm.
The smalleye spaghetti-eel is an eel in the family Moringuidae. It was described by Charles Henry Gilbert in 1890. It is a tropical, marine eel known from the eastern central and southeastern Pacific Ocean, including Mexico, Colombia, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, and Panama. It is known to dwell at an approximate depth of 55 m, and inhabits substrates, burrowing into mud and sand. Its diet consists primarily of shrimp, crabs, benthic gastropods, bivalves, and worms.
Coloconger canina is an eel in the family Colocongridae. It was described by Peter Henry John Castle and Solomon N. Raju in 1975. It is a marine, deep-water dwelling eel which is known from leptocephali collected from the Indian Ocean. It is known to dwell at a minimum depth of 300 m.
Coloconger eximia is an eel in the family Colocongridae. It was described by Peter Henry John Castle in 1967, originally under the genus Ascomana. It is a marine, deep-water dwelling eel which is known from Cape Peninsula, South Africa, in the southeastern Atlantic Ocean.
The Maimed snake eel is an eel in the family Ophichthidae. It was described by Pieter Bleeker in 1857. It is a marine, tropical eel which is known from the Indo-Pacific, including the Red Sea, East Africa, Samoa, the Ryukyu Islands, Australia, and Micronesia. It dwells at a depth range of 1 to 13 metres, and inhabits coral reefs and lagoons, where it forms burrows in soft benthic sediments. Males can reach a maximum total length of 24 centimetres (9.4 in), but more commonly reach a TL of 8 centimetres (3.1 in).
The Smallfin worm-eel is an eel in the family Ophichthidae. It was described by Charles Barkley Wade in 1946. It is a marine, tropical eel which is known from the eastern central and southeastern Pacific Ocean, including Nicaragua, Colombia, Panama and Costa Rica. It dwells at a depth range of 100 to 200 metres, and inhabits sediments of mud. Males can reach a maximum total length of 16 centimetres (6.3 in).
The Johnston snake eel, also known as the peppered worm eel in Micronesia and Hawaii is an eel in the family Ophichthidae. It was described by Leonard Peter Schultz and Loren Paul Woods in 1949. It is a marine, tropical eel, which is known from the Indo-Pacific region, including the Chagos Islands, Hawaii, the Marquesan Islands, the Society Islands, Australia, and New Caledonia. It dwells at a depth range of 2–23 m, and inhabits sand sediments in coral reefs. It can reach a maximum total length of 35 cm.
The shortfinned worm eel is an eel in the family Ophichthidae. It was described by William John Macleay in 1881, originally under the genus Muraenichthys. It is a marine, temperate water-dwelling eel which is known from Australia, in the southwestern Pacific Ocean. It forms large colonies which inhabit burrows in soft sediments. Males can reach a maximum total length of 40 centimetres (16 in).
The deepwater big-eyed worm eel is an eel in the family Ophichthidae. It was described by John E. McCosker in 2006. It is a subtropical, marine eel which is known from New Zealand, in the southwestern Pacific Ocean. It dwells at a depth range of 425–820 metres. Females can reach a maximum total length of 58 centimetres.
The Indo-Pacific slender worm-eel is an eel in the family Ophichthidae. It was described by Pieter Bleeker in 1857. It is a marine, tropical eel which is known from the Indo-Pacific, including the Red Sea, East Africa, the Line Islands, the Society Islands, Johnston Island, Japan, Rapa Iti, Micronesia, and the southern Great Barrier Reef. It forms burrows in inshore sediments of loose gravel and sand. Males can reach a maximum total length of 38 centimetres (15 in).
The slender snake eel is an eel in the family Ophichthidae. It was described by Pieter Bleeker in 1857. It is a marine, tropical eel which is known from the Indo-Pacific, including East Africa, the Society Islands, the Ryukyu Islands, and the Great Barrier Reef. It dwells at a depth range of 30 to 33 metres, and inhabits sand sediments, tidepools and swamps in mangroves. Males can reach a maximum total length of 25 centimetres (9.8 in).
The angry worm eel is an eel in the family Ophichthidae. It was described by Peter Henry John Castle and John E. McCosker in 1999. It is a tropical, marine eel which is known from the eastern Indian and western central Pacific Ocean, including India, Indonesia, the Straits of Malacca, northern Australia, and the Philippines. It is known to inhabit shallow, turbid estuaries, and to a lesser extent the deeper water over soft substrates. Males can reach a maximum total length of 29.6 centimetres.
The Finned worm eel is an eel in the family Ophichthidae. It was described by Coenraad Jacob Temminck and Hermann Schlegel in 1846. It is a marine, tropical eel which is known from the Indo-Pacific, including East Africa, the Society Islands, and southern Japan. It is known to dwell in reefs. It is the only worm eel in its region which possesses pectoral fins. Males can reach a maximum total length of 60 centimetres.
The saddled snake-eel is an eel in the family Ophichthidae. It was described by George Tradescant Lay and Edward Turner Bennett in 1839, originally under the genus Ophisurus. It is a marine, tropical eel which is known from the Indo-Pacific and southeastern Atlantic Ocean, including East and South Africa, the Hawaiian Islands, the Marquesan Islands, the Mangaréva islands, Japan, and Australia. It dwells at a depth range of 0 to 70 metres, most often around 0 to 10 metres, and inhabits lagoons and reefs, in which it forms burrows in beds of seagrass and sandy areas. Males can reach a maximum total length of 66 centimetres (2.17 ft).
The dark-shouldered snake eel is an eel in the family Ophichthidae. It was described by Pieter Bleeker in 1864. It is a tropical, marine eel which is known from the Pacific Ocean, including the East Indies, the Society Islands, the Mariana Islands, Queensland, the Marshall Islands, Micronesia, Japan, and India. It dwells at a depth range of 2–15 metres, and inhabits reefs. It forms burrows in mud and sand, and forages during the night. Males can reach a maximum total length of 115 centimetres.
The many-eyed snake eel is a species of eel in the family Ophichthidae. It was described by Pieter Bleeker in 1864. It is a tropical, marine and freshwater-dwelling eel which is known from the Indo-Pacific, including East Africa and the Hawaiian Islands. It dwells at a depth of 2 to 25 metres, and inhabits sand and rubble sediments near coral reefs. Males can reach a total length of 62.5 centimetres (24.6 in).
