In this post, we will learn about Snake-like Fish, focusing on the most popular group of snake-like species commonly encountered during dives, the Moray eels.
What are Snake-like Fish?
There are many fish that look like snakes. These are the Eels, Snakehead fish, Lamprey, and others. However, the most common group of snake-like fish are the eels, mainly the Moray eels.
Moray eels are teleost fish, members of the Anguilliformes, belonging to the Muraenidae family. One of their main characteristics is their elongated and cylindrical snake-like body. There are more than 200 species of moray eels grouped within 15 genera.
They have an appearance that resembles a snake but they are part of the eel group. They do not have scales, and for their protection, some species secrete mucus composed of toxins over their skin. Most do not have pectoral and pelvic fins but have a unique fused fin, formed by three soft and articulated rays. These rays start on the back and end at the anus, passing through the end of the tail. Their skin is made up of colour patterns that serve as camouflage.
They inhabit tropical and subtropical Atlantic waters. These are animals have solitary and nocturnal habits, going out in search of food in the middle of the night. Moray eels are carnivorous and their diet is based on crustaceans, fish, and octopuses.
During the day, they live on reefs holes or under rocks, keeping their heads out and their mouths open. In this way, their very sharp teeth are exposed, giving it a frightening appearance, scaring away other animals, except for one fish, the cleaner fish. They have approximately 10 cm long, which has a symbiotic relationship with the moray. This little animal cleans the moray skin and removes bits of food stuck in its sharp teeth.
Moray eels are not aggressive, on the contrary, they are shy animals, but accidents involving divers can happen if this fish mistakes a human finger for an octopus tentacle. Its bite causes serious accidents, and some species have venom, which they inoculate when biting.
At the time of hatching and in the critical phase of life, the hatchlings display a transparent plant leaf appearance and are called leptocephalus.
Green moray
This species is from the same Muraenidae family, but the green moray is characteristically green, as its name suggests. The species is found at depths up to 40 meters and has a length of 2.5 metres. Smaller, therefore, than other fish from the same family.
It is present in the western Atlantic, from New Jersey, passing through Bermuda and north of the Gulf of Mexico, reaching Brazil.
Giant moray eel
This species is the largest of the Muraenidae family, which can reach up to 3 metres in length and weigh 30 kilos. The young giant moray is cinnamon in colour with huge black spots. On the other hand, an adult individual only keeps the black spots around the gill opening.
The giant moray has poor eyesight, so it depends even more on its sense of smell to hunt. A curiosity, however, is that it searches for its prey along with the coral grouper, of the species Plectropomus pessuliferus. To give you an idea, it is the only cooperative joint where different families get together to hunt.
The invitation to the joint work is made through a nod of the head. Cooperative hunting between the two animals takes place because the grouper cannot enter the narrow holes where the prey is. Thus, the giant moray, which has the thinnest body, penetrates the crevices and grasps the prey that serves as food for the grouper.
The giant moray also eats other morays, in addition to molluscs and fish. It migrates on a journey of more than 6 thousand kilometres, over seven months, for reproduction. Interestingly, after giving birth the female dies. It is found in the Indo-Pacific region, the Andaman Sea, Red Sea, East Africa, Pitcairn Islands, Hawaii and Ryukyu Islands, New Caledonia, Fiji, and the Austral Islands.
Moray eel Facts
They have two sets of jaws
Like the monster in Alien (1979), morays attack their victims with a hidden set of choppers. Inside the throat, there is a pair of hidden pharyngeal jaws that help the eel trap its prey. While most predatory fish use suction to pull food down their throats, moray eels use a two-step strategy. First, the outer claws firmly hold the target. Then the pharyngeal joint shoots forward bite the unfortunate victim and pulls it toward the throat.
There are 200 known species
The family is divided into two main groups: true eels and snake eels. The first is more common, with around 166 species currently recognized. Anatomically, the fins represent the biggest difference between these two groups, while the dorsal fin of a true moray starts right behind its gills, it is limited to the tail region of snake morays.
The biggest eel can weigh at least 29 kilograms
The largest species is named Giant moray (Gymnothorax javanicus). So far, the most sizable individuals recorded were almost 3 metres long and weighed 66 kilograms. But there are unconfirmed reports of monstrous 3.5 metres morays swimming around. Divers can spot these animals in the Red Sea, the east coast of Africa, and across the Indo-Pacific.
Special teeth
The medium moray comes with curved teeth, ideal for catching fish. Still, some varieties such as the Zebra moray (Gymnomuraena zebra) feed on crabs, molluscs, molluscs, and sea urchins. Which requires strong jaws and specialized ground teeth, so its pearly whites are unusually rough.
Most Morays have nocturnal habits
In general, Moray eels are active after the sun goes down, although the Chain moray eel, Echidna catenata, for example, have more diurnal lifestyles.
The Green moray (Ginánotoxic Funebris) is brown
It only looks green because, like many moray eels, the animal drives away predators, secreting a layer of mucus that covers its skin. This slime contains several toxins, including one that destroys red blood cells. While green moray eels are dark brown the yellowish hue of the mud gives them a more vibrant tone.
Moray eel distribution
The Moray eel lives in both fresh water and saltwater environments, depending on the species. It is a fact that they also like faster moving water rather than calm places. Not to mention that they seem to be able to thrive in warmer bodies of water.
Species reproduction
There is no definite mating season for the morays. They tend to do this when they have enough food and habitat availability. Moray eels, like all true eels, are oviparous. Warmer water temperatures also increase the chances of successful mating.
Female morays will find a place to lay their eggs, where they will be well hidden. They will release an odour as they do this, allowing the males to approach and deposit their sperm as well. It can take 30 to 45 days for the hatchlings to emerge. If the water temperature warms, they will hatch in fewer days.
How to raise moray eels?
Raising moray eels is not such a difficult task. But, take special care and you must ensure that the animal receives the proper treatments.
One of them is to preserve the environment in which the moray is inserted, providing a place of calm and tranquillity. Remember that moray eels are extremely irritable fish. When they receive a lot of stimuli, they can go into a very deep state of stress. This will make them have impulsive behaviours or stop eating.
It is also essential to maintain water quality levels, especially if the moray’s previous habitat is a saline environment. A sea moray, that is, used to saltwater, if deposited in a freshwater tank, will, over time, develop several health problems that could easily be avoided with correct water maintenance.
Naturally curious, moray eels tend to look for gaps and indentations in search of food. Therefore, keep in aquariums with lids very tightly closed. Otherwise, they may run out.
Aquariums necessarily need to have a landscape that resembles the natural environment of moray eels.
Conclusion
In this post, we learnt about Snake-like Fish, focusing on the most popular group of snake-like species commonly encountered during dives, the Moray eels.
If you have any thoughts or doubts, feel free to drop us in a comment below!
Frequently Asked Questions (FAQs): Snake-like
What is the morays’ shelter?
Morays live at depths ranging from the surface to a hundred meters, where they spend most of their time hidden inside cracks and small caves, where they rest during the day.
What is the biggest moray in the Atlantic Ocean?
The green moray is classified as the largest moray in the Atlantic Ocean, reaching up to 2.5 metres in length in its habitat, although in the ornamental market it is more common to find specimens up to 1 metre.
What is the danger of the moray?
Moray eels are not aggressive, on the contrary, they are shy animals, but accidents involving divers can happen. Its bite causes serious accidents, and some species have venom and other cause severe infections.
How many metres does a Giant moray reach?
The largest Giant moray reached around 3 meters in length.
What does moray eat?
Moray eels are carnivores, feeding mainly on smaller fish, octopuses, squid, cuttlefish, and crustaceans.
References
Murata, M., Legrand, A. M., Ishibashi, Y., Fukui, M., & Yasumoto, T. (1990). Structures and configurations of ciguatoxin from the moray eel Gymnothorax javanicus and its likely precursor from the dinoflagellate Gambierdiscus toxicus. Journal of the American Chemical Society, 112(11), 4380-4386.
Bowman, T. E. (1960). Description and notes on the biology of Lironeca puhi, n. sp.(Isopoda: Cymothoidae), parasite of the Hawaiian moray eel, Gymnothorax eurostus (Abbott). Crustaceana, 84-91.
Reece, J. S., & Mehta, R. S. (2013). Evolutionary history of elongation and maximum body length in moray eels (Anguilliformes: Muraenidae). Biological Journal of the Linnean Society, 109(
