The Fimbriated Moray Eel (Gymnothorax fimbriatus) is also known as the spot-face moray, the darkspotted moray and the Cheetah Moray. They are rare in Tanzanian waters and we have sighted very few specimens, to our knowledge they have not been recorded here before.
The Fimbriated Moray Eel grows up to 80cm in length. Its serpentine shape body has an undulating pattern of lines that form a pattern down its body. The head is a light green colour and the body is a light yellow colour. The head and body are covered in irregular black spots and there are distinctive white marks in the corner of the mouth. Behind the head there is a slight thickening and the head is small compared to other moray eels with proportionally large eyes located forward. Fimbriated Moray Eel have a second set of jaws known as pharyngeal jaws in their throat which may partially account for their thickened neck.
The mouth has large teeth for tearing flesh rather than grinding. They do not have pectoral or pelvic fins and the dorsal fin runs the length of the body.
IN THE WILD
Fimbriated Moray Eels are usually nocturnal feeders and spend the days in crevices in the rocks. Very occasionally one may be seen out in the open during the day but this is rare. If they are seen out in the open then they are low on the bottom and moving in a snake like fashion between rocks rather than swimming. They will usually take off in the opposite direction when they see you.
Moray eels have proportionately small circular gills, located on posterior of the mouth and the moray is constantly opening and closing its mouth to facilitate sufficient water flow over its gills. In general the opening and closing of the mouth is not threatening behavior but one should not approach too closely. They will bite if threatened. We have only seen the Fimbriated Moray Eels on walls off Dar es Salaam at about 35 meters in depth.
Some researchers speculate that moray eels contain toxins in their mouths and are poisonous. From many years of catching crayfish on the Kwa Zulu Natal coast I have never had a bite go sceptic. After every bite I have soaked the bite area in hot water as hot as I could take it. Much of the bite damage occurs when one pulls ones hand back after being bitten. Many experts state that one should not pull back, however they should go try it themselves. The bite is usually sudden and unexpected and it is natural to pull away from it. I have personally seen one diver who lost the use of his thumb from a giant moray bite but that is unusual.
Morays secrete mucus over their scaleless skin, which in some species contains toxins. They have a thick skin and a large number of cells that secrete mucus in the epidermis.
The Fimbriated Moray Eel is widespread across the Indo-Pacific area, being found from the East Coast of Africa from south of Durban northwards, Red Sea included, across to the Pitcairn group, Hawaiian islands and Polynesia. North to south in Japan and south to New Caledonia, Fiji and Australia.
They are found in rocky reefs, coral reefs and occasionally in lagoons provided there is shelter. They are found from depths of 1 to 50 meters.
The Fimbriated Moray Eel is carnivorous, and does most of its hunting at night. They feed mainly on small fish and crustaceans but the fact that they are on occasion caught by fishermen using bait indicates that they will scavenge as well. Moray Eels have relatively poor eye sight but they have an excellent sense of smell that they use to detect their prey.
Moray eels have a second set of jaws in their throat called pharyngeal jaws, which also have teeth. When feeding, morays latch onto the prey with their outer jaws. They then push their pharyngeal jaws which are set back in the pharanx, forward into the mouth. They then grasp the prey and pull it into the throat and stomach. Moray eels are the only fish that use pharyngeal jaws to capture prey. Their main hunting tool is their excellent sense of smell which makes up for their poor eyesight. This means that weakened or dead creatures are the moray eel’s favoured food.
Studies have shown hermaphroditism in morays, some being sequential and others synchronous which can reproduce with either sex. Courtship usually occurs when water temperatures are high. After posturing to each other they wrap their bodies around each other and simultaneously release sperm and eggs. Once they hatch the larvae float in the ocean for around 8 months before becoming elvers and eventually a moray eel.
Ciguatoxin, the main toxin of ciguatera, is produced by a toxic dinoflagellate and accumulated up through the food chain, of which moray eels are top, making them potentially dangerous for humans to eat. They are fished and do take bait. There is documented evidence of Ciguatoxin poisoning from some species of moray eels and because of this they should not be eaten.
Once caught on a line they are extremely troublesome to deal with. They wrap around the line and secrete a large amount of mucus. Unless the line is changed, much as with the mucus from puffer fish, no other fish will bite on the line. It is not uncommon for a caught moray eel to actually bite its self while it is busy wrapping around the line.
Because of their size, as a rule Fimbriated Moray Eelss are usually only kept in public aquariums but some specialist aquarists keep them in species specific tanks.