American Eel (Anguilla rostrata)

The American Eel lives in the far-flung corners of the North Atlantic. It has a snakelike body and can grow up to five feet, though most individuals measure only two to three feet. 

Its skin ranges from yellow to green-brown, and it has a lighter belly, camouflaging it in riverbeds and coastal waters.

These types of eels are both freshwater and saltwater eels. They spend most of their lives in freshwater or brackish environments. However, during the breeding season, they migrate to the ocean. 

Additionally, these true eels eat various prey, such as insects, crustaceans, and fish. At night, the American eel emerges from the sand to hunt. They also don’t hesitate to step onto land for food.

European Eel (Anguilla anguilla)

The European Eel can grow up to 5 feet long and camouflage itself in its environment. Moreover, they are nocturnal hunters that feed on insects, crustaceans, mollusks, and other small aquatic animals.

Additionally, European Eels are catadromous; they spend most of their lives in freshwater or brackish waters and travel to the Sargasso Sea to breed1. 

They turn from larvae to glass eels during their journey, then to yellow and silver eels. These types of eels can also breathe through their skin, enabling them to survive short periods of drought.

Japanese Eel (Anguilla japonica)

The Japanese Eel lives off the coast of Japan, Korea, Vietnam, and the northern regions of the South China Sea. They are olive green, tranquil brown, white, or soft yellow. Moreover, they have small heads with large eyes that help them see in the dark.

The Japanese Eel migrates most of its time in freshwater or brackish waters. During the breeding season, they migrate into the ocean, swimming hundreds, or even thousands, of miles to reach spawning grounds in the far West of the North Pacific Ocean.

Part of the eel life cycle is the development of leptocephali, offspring that rely on ocean currents to guide them back to their freshwater habitats for several months3.

The mottled eel

The mottled eel (Anguilla bengalensis), also known as the African mottled eel, the Indian longfin eel, the Indian mottled eel, the long-finned eel or the river eel is a demersal, catadromous eel in the family Anguillidae. It was described by John McClelland in 1844. It is a tropical, freshwater eel which is known from East Africa, Bangladesh, Andaman Islands, Mozambique, Malawi, Sri Lanka, Sumatra, and Indonesia and recently from Madagascar. The eels spend most of their lives in freshwater at a depth range of 3–10 metres, but migrate to the Indian Ocean to breed. Males can reach a maximum total length of 121 centimetres and a maximum weight of 7,000 grams. The eels feed primarily off of benthic crustaceans, mollusks, finfish and worms.

Indonesian Shortfin Eel (Anguilla bicolor bicolor)

The Indonesian Shortfin Eel is a deep-brown to light-yellow eel that inhabits the Indian Ocean, Western Pacific Ocean, and Indonesian waters. It is a unique subspecies of the Shortfin Eel, characterized by its shorter dorsal fin beyond the pectoral fins. This catadromous eel lives in freshwater rivers and streams.

During the breeding season, these eels swim against the current and return to the ocean. Moreover, the Indonesian Shortfin Eel embarks on land excursions, using its slender body and sharp pectoral fins to explore new territories. They undertake these journeys at night when they emerge from their burrows and crevices.

Scanning their surroundings for prey, they mainly feed on small fish, crustaceans, and other invertebrates.

African Longfin Eel (Anguilla mossambica)

The African longfin eel[3] (Anguilla mossambica), also known simply as the longfin eel, is an eel in the family Anguillidae.[4] It was described by Wilhelm Peters in 1852, originally under the genus Muraena.[5] It is a tropical eel known from freshwaters in southern Kenya, Cape Agulhas, Madagascar, and New Caledonia. The eels spend most of their lives in freshwaters far inland, but migrate to the Western Indian Ocean to breed. Males can reach a maximum total length of 150 centimetres; females can reach a maximum standard length of 120 centimetres and a maximum weight of 5,000 grams. The eels can live for about 20 years.[4] Juveniles and adults are known to feed off of carcasses, crabs, and bony fish.[6]

Zebra Moray Eel (Gymnomuraena zebra)

The Zebra Moray Eel has a body pattern of alternating black and white stripes. It commonly lives in the coral reefs of the Indo-Pacific region, including the Red Sea, Hawaii, and the eastern coast of Africa. The eel's teeth are shaped like molars, crushing crustaceans such as shrimp, crabs, and mollusks before eating them.

Despite its unique appearance and eating habits, this type of eel is peaceful. When approached by divers or snorkelers, it retreats to rocky shelters.

New Zealand Longfin Eel (Anguilla dieffenbachii)

The freshwater habitats of New Zealand are home to the New Zealand Longfin Eel. These eels can grow up to 6.6 feet long, with females reaching this maximum size. Hence, the New Zealand Longfin Eel is one of the world’s largest eel species. 

These eels are olive green to brown. Their long dorsal fins are notable features; they undulate gracefully, helping them move quietly during nocturnal hunts. Despite their size, they are shy creatures.

During the day, they hide in shadowy locations, such as submerged logs or unseen crevices. Their keen sense of smell helps them find prey, primarily invertebrates, small mammals, and other fish.

Moreover, these eels can live for over a century but only breed once. During the breeding season, they embark on an epic journey from their freshwater homes to their spawning grounds in the deep Pacific Ocean near Tonga. After mating, the eels die. Then, thousands of minute larvae return to New Zealand, guided by the waves.

Australian Longfin Eel (Anguilla reinhardtii)

The speckled longfin eel, Australian long-finned eel or marbled eel (Anguilla reinhardtii) is one of 15 species of eel in the family Anguillidae. It has a long snake-like cylindrical body with its dorsal, tail and anal fins joined to form one long fin. The dorsal fin also often extends farther than the anal fin. It usually has a brownish green or olive green back and sides with small darker spots or blotches all over its body. Its underside is paler.[2] It has a small gill opening on each side of its wide head, with thick lips. It is Australia's largest freshwater eel, and the female usually grows much larger than the male.[2][3] It is also known as the spotted eel.

Southern Shortfin Eel (Anguilla australis)

The Southern Shortfin Eel typically inhabits cooler freshwater areas in Australia, New Zealand, and Tasmania. This species is dark brown and olive green, with a lighter underbelly and a shorter dorsal fin. Due to their snake-like locomotion, they can briefly go on land.

The Southern Shortfin Eel also starts life in the deep Coral Sea, turning from larvae into transparent glass eels. Braving numerous challenges, these eels journey from their birthplace to freshwater habitats. Female eels are larger than males, growing up to 3.3 feet long.

These types of eels prefer to stay hidden during the day under rocks and vegetation. They are active at night, feeding on fish, crustaceans, insects, and worms.

Purple Spaghetti Eel (Moringua raitaborua)

The purple spaghetti-eel[2] (Moringua raitaborua) is an eel  in the family Moringuidae  (spaghetti/worm eels).[3] It was described by Francis Buchanan-Hamilton in 1822, originally under the genus Muraena.[4] It is a tropical eel known from India, Bangladesh, Nepal, Indonesia, and the Philippines. It inhabits rivers  and estuaries (including ones in West Bengal, linked to the Ganges River), and has adapted to rapid and wide changes in salinity, pH, and osmoregulatory and hypoxic conditions.[5] Males can reach a maximum standard length of 44 cm.

Snake Eel (Ophichthidae)

Snake eels or worm eels look like snakes with long bodies and a scaled texture. They range in color from brown to bright hues and often have patterns serving as camouflage. They live in marine, brackish, and sometimes freshwater environments and spend most of the day burrowed in sand or mud. 

This type of eel has a forward escape technique—they disappear by moving forward, not backward, into the sand. Additionally, their hard, pointed tails are uniquely adapted for burrowing. These traits showcase the fascinating adaptability of life underwater.

Pike Conger Eel (Muraenesox bagio)

Pike conger eels can live in fresh and saltwater environments, although they typically prefer saltwater. These eels can grow from two to eight feet long and survive depths of up to 2624.67 ft.

Approximately fifteen different species of pike conger eels live around the world.

Sawtooth Eel (Serrivomeridae)

Sawtooth eels are pelagic fish living in the dark depths of the ocean. Their name comes from their inward-facing saw-like teeth. This type of eel comprises around eleven species; most sawtooth eels have a maximum size of 24 to 28 in.

Mediterranean Moray Eel (Muraena helena)

Growing up to 5 feet, this long, slender eel moves quickly through the rocky reef environment. The Mediterranean Moray Eel ranges from dark brown to soft grey, with a yellowish underbelly. It doesn't have pectoral fins.

This eel feeds on fish, squids, and octopuses. However, it's far from the top of the food chain as larger fish and marine mammals like seals and sea lions also prey on them.

Moreover, the Mediterranean Moray Eel forces water over its gills to breathe, requiring it to open and close its mouth rhythmically.

Giant Moray Eel (Gymnothorax javanicus)

The Giant Moray Eel lives in the Indo-Pacific region's rocky seafloors and coral reefs. It is the world's largest moray eel, measuring 10 feet and weighing over 66 pounds. (The Slender Giant Moray Eel is longer.) Its brown skin has a unique dark spot pattern contrasting with the colorful reefs.

Moreover, this nocturnal eel hides in crevices and caves to avoid predators and rest for its nighttime hunts for fish, cephalopods, and crustaceans. 

The Giant Moray Eel also forms alliances with coral groupers to hunt prey. It chases prey into open waters while the grouper takes advantage.

California Moray Eel (Gymnothorax mordax)

The California Moray Eel lives in the moonlit kelp forests of the eastern Pacific. Their color palette ranges from bronze to olive green and can grow up to 60 in long, although most average around 24 in. Despite their size, they are shy and spend their days hidden in rocky alcoves, away from other marine life.

At nightfall, the California Moray Eel becomes active and relies on its sense of smell to locate small fish or various invertebrates. It creates a cloud of slime to trap and paralyze its victim against the reef or kelp.

Additionally, the eel starts life as a female and becomes a male as it matures through a phenomenon called protogyny. 

The California Moray is a primarily solitary species that mainly interacts with others during mating.

Longfin African Conger (Conger cinereus)

The Longfin African conger lives in the Indo-Pacific oceans, from the Red Sea and East Africa to the Marquesas and Easter Islands. They can survive depths of 262 feet, growing up to 4.3 feet long.

This type of eel feeds on small fish and crustaceans. It has an elongated body and fin extending from just behind the head to the tip of the tail, earning it the name 'Longfin.'

Snowflake Moray Eel (Echidna nebulosa)

The Snowflake Moray Eel has a distinctive pattern of black splotches resembling snowflakes. It is a relatively small eel, typically up to 24 inches long. They live in the tropical Indo-Pacific region, among coral reefs and rock formations in warm summer waters.

The nocturnal Snowflake Moray Eel spends the day in reef crevices to avoid the sun. It is skilled enough to navigate its underwater labyrinth and hunt for food at night. Moreover, its long, flexible body allows it to probe into narrow corners and crevices, looking for small fish and crustaceans.

The Snowflake Moray Eel is peaceful when not on the hunt, attracting aquarium owners worldwide.

Green Moray Eel (Gymnothorax funebris)

The Green Moray Eel inhabits the deep, shadowy waters of the western Atlantic Ocean. Green Moray Eels can grow up to 7.2 feet long and weigh approximately 64 lbs.

Despite its name, this species is not green, but its natural color is soft brown with a layer of yellow mucus. When hit by light, this mucus gives the appearance of vibrant green. 

These types of eels periodically open and close their mouths because their gills require a continuous flow of water for breathing. They eat mainly fish, squids, and crabs. Lastly, they hide in dark crevices of coral reefs or rocky underwater terrains during the day and come out at night to hunt.