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.
The garden eels are the subfamily Heterocongrinae in the conger eel family Congridae. The majority of garden eels live in the Indo-Pacific, but species are also found in warmer parts of the Atlantic Ocean and East Pacific. These small eels live in burrows on the sea floor and get their name from their practice of poking their heads from their burrows while most of their bodies remain hidden. Since they tend to live in groups, the many eel heads "growing" from the sea floor resemble the plants in a garden. They vary greatly in colour depending on the exact species involved. The largest species reaches about 120 cm (47 in) in length, but most species do not surpass 60 cm (24 in). Garden eel colonies can grow as large as one acre in surface area.
The Barnes' garden eel is an eel in the family Congridae. It was described by Bruce H. Robison and Thomas M. Lancraft in 1984. It is a marine, tropical eel which is known from the western Pacific Ocean, including Indonesia, the Philippines, Vanuatu, the Solomon Islands and Papua New Guinea. It dwells at a depth range of 5 to 20 metres, and inhabits sand substrates. Males can reach a maximum total length of 121 centimetres (48 in).
The Hawaiian garden eel is an eel in the family Congridae. It was described by John Ernest Randall and James Robert Chess in 1980. It is a marine, tropical eel which is known from the Hawaiian archipelago, in the eastern central Pacific Ocean. It is non-migratory, and is thought to be restricted to the region. It dwells at a depth range of 11 to 53 metres, and leads a benthic life, forming burrows in sand. Males can reach a maximum standard length of 59.8 centimetres (23.5 in).
Gorgasia inferomaculata is an eel in the family Congridae. It was described by Jacques Blache in 1977. It is a non-migratory marine, tropical eel which is known from the Gulf of Guinea, in the eastern central Atlantic Ocean.
The Pacific spaghetti eel is a sand dwelling eel in the family Congridae. It was described by Tokiharu Abe, M. Miki and Minoru Asai in 1977. It is a marine, temperate water-dwelling eel which is known from the northwestern and southwestern Pacific Ocean, including Japan and New Zealand. It dwells at a maximum depth of 30 metres (98 ft). It is non-migratory, and inhabits sand flats near reefs. Males can reach a maximum total length of 100 centimetres (39 in); the diameter of the body is approximately 10 millimetres. Spaghetti eels will typically occur in large groups that can consist of hundreds of eels.
The Klausewitz's garden eel is an eel in the family Congridae. It was described by Jean-Claude Quéro and Luiz Vieria Caldas Saldanha in 1995. It is a marine, tropical eel, which is known from the Indian Ocean, including the Andaman Islands, Réunion, Mauritius, and the Comoros Islands. It dwells at a depth range of 170 to 225 metres, and forms large colonies consisting of hundreds of individual eels. Males can reach a maximum total length of 75.1 centimetres (29.6 in).
The whitespotted garden eel, also known as the Indian spaghetti eel, is an eel in the family Congridae. It was described by Wolfgang Klausewitz and Irenäus Eibl-Eibesfeldt in 1959. It is a marine, tropical eel which is known from the Indo-Western Pacific, including Maldives, the Solomon Islands, the Philippines, the Cocos Islands, Comoros, India, Indonesia, and Papua New Guinea. It dwells at a depth range of 25 to 48 metres, and lives in non-migratory colonies that form burrows on sandy slopes, usually near coral reefs. Males can reach a maximum total length of 70 centimetres (28 in).
Gorgasia naeocepaea, the freckled garden eel, is an eel in the family Congridae. It was described by James Erwin Böhlke in 1951, originally under the genus Taenioconger. It is a marine, tropical eel which is known from the western central Pacific Ocean, including the Philippines and Indonesia. It is known to inhabit sandy regions, and dwells at a depth range of 10 to 24 metres. Males can reach a maximum total length of 75 centimetres (30 in).
The dotted garden eel, also known as the peppered garden eel, is an eel in the family Congridae. It was described by Seth Eugene Meek and Samuel Frederick Hildebrand in 1923. It is a nonmigratory tropical, marine eel which is known from the eastern central Pacific Ocean, including Costa Rica, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, and Panama. Males can reach a maximum total length of 50 cm.
Gorgasia sillneri is an eel in the family Congridae. It was described by Wolfgang Klausewitz in 1962. It is a marine, tropical eel which is known from the Gulf of Aqaba in the Red Sea, in the western Indian Ocean. Males can reach a maximum total length of 83.8 centimetres (33.0 in).
The sharp-nose garden eel is an eel in the family Congridae. It was described by Shao Kwang-Tsao in 1990. It is a marine, subtropical eel which is known from Taiwan and southern Japan, in the northwestern Pacific Ocean. It is non-migratory, and dwells at a depth range of 14 to 22 metres. Males can reach a maximum total length of 74.1 centimetres (29.2 in). It can be identified by the shape of its snout.
Gorgasia thamani is an eel in the family Congridae. It was described by David Wayne Greenfield and Sean Niesz in 2004. It is a marine, tropical eel which is known from Fiji, in the western central Pacific Ocean. It is known to dwell at a depth range of 14 to 15 metres. Males can reach a maximum total length of 119 centimetres (47 in).
Heteroconger congroides is an eel in the family Congridae. It was described by Umberto D'Ancona in 1928, originally under the genus Leptocephalus. It is a marine, deepwater-dwelling eel which is known from the Kamaran Islands in Yemen, in the Red Sea, in the western Indian Ocean. It is known only from larvae, which are known from a depth of 522 m (1,713 ft).
The Guinean pike conger is an eel in the family Muraenesocidae. It was described by Oronzio Gabriele Costa in 1846. It is a marine, subtropical eel which is known from the eastern Atlantic Ocean, including Gibraltar, the western Mediterranean, and Angola. It dwells at a depth range of 10 to 100 metres ; larger individuals are usually found from 75 to 100 metres. It inhabits sand and mud substrates on the continental shelf. Males can reach a maximum total length of 200 centimetres (79 in), but more commonly reach a TL of 150 centimetres (59 in).
Gavialiceps arabicus is an eel in the family Muraenesocidae. It was described by Umberto D'Ancona in 1928, originally under the genus Leptocephalus. It is a marine, deep water-dwelling eel which is known from the western Indian Ocean, including the Gulf of Aden, the southeastern Arabian Sea, Socotra, Yemen and Maldives. It dwells at a depth range of 380 to 497 metres. Males can reach a maximum total length of 84 centimetres.
The Facciola's sorcerer, also known as the Facciola sorcerer in Uruguay is an eel in the family Nettastomatidae. It was described by Cristoforo Bellotti in 1883. It is a marine, subtropical eel which is known from the eastern Atlantic Ocean, including southern Portugal, Angola, and the Ligurian and Tyrrhenian seas. It dwells at a depth range of 30–731 metres; the young are known to inhabit caves, in which the larger specimens are found deeper. Males can reach a maximum standard length of 64.9 centimetres.
Facciolella saurencheloides is an eel in the family Nettastomatidae. It was described by Umberto D'Ancona in 1928. It is a marine, deep water-dwelling eel which is known from the northwestern and western Indian Ocean, including the Red Sea. It dwells at a depth range of 700–2000 metres.
Ophichthus echeloides is an eel in the family Ophichthidae. It was described by Umberto D'Ancona in 1928. It is a marine, tropical eel which is known from the Gulf of Aqaba and the Red Sea, in the western Indian Ocean. Males can reach a maximum total length of 51 centimetres (20 in).
Dysomma brevirostre, the pignosed arrowtooth eel or batnose eel, is an eel in the family Synaphobranchidae. It was described by Luigi Facciolà in 1887. It is a marine, deep water-dwelling eel which is known from the eastern and western Atlantic Ocean, including Madeira Island, the Gulf of Guinea, the Ligurian Sea, Italy, and Florida and Hawaii, USA. It dwells at a depth range of 200 to 1,000 metres, and inhabits soft sediments on the continental slope. Males can reach a maximum total length of 30 centimetres (12 in).
