The zebra moray, Gymnomuraena zebra as its name implies is a dark colored moray with white stripes. They are one of the more reclusive moray eels. As they are nocturnal they are not commonly seen.
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 can take it. Much of the bite damage occurs when one pulls ones hand back after being bitten. Many experts say 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 epidermis. 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.
IN THE WILD
The zebra moray eel are not generally seen protruding from a hole or small cave as are most morays. Usually during the day they can only be seen deep in caves or holes and seldom if ever put their head out. They are not as aggressive as the other morays but should be treated with caution because they will bite if threatened. They feed at night and are occasionally seen on night dives as in these images. Compared to other morays they are very reclusive. At night as soon as one encounters one they tend to head for shelter and do not enjoy the light.
Moray eels have proportionately small circular gills, located on posterior of the mouth. As a result 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 grow over a meter in length in the wild but most are around a meter in length.
The white-mouth moray eel is found across the Indian ocean and in the Pacific. They are found as far west as the Gulf of California and the Galapagos Islands.
The zebra moray eel is carnivorous, and does most of its hunting at night. They feed mainly on crustaceans, mollusks and sea urchins. With their short blunt grinding teeth they are able to crush their prey and grind the meat out. As with most other morays they will probably feed on carrion if the opportunity presents its self.
Moray eels have a second set of toothed jaws in their throat called pharyngeal jaws. When feeding, morays latch onto the prey with their outer jaws. They then push their pharyngeal jaws, which are set back in the pharynx, forward into the mouth. These jaws then grasp the prey and pull it back into the 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.
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. This makes them potentially dangerous for humans to eat. They are fished and do take bait but because of the toxins should not be eaten.
Once caught they are extremely troublesome to deal with. They wrap around the line and secrete a large amount of mucus and as a result the line has to be changed. As with the mucus from puffer fish, no other fish will bite on the line once it has the mucus on it. 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 attractive looks and their diet they are kept in aquariums. As their diet comprises of crustaceans, mollusks and sea urchins, they are reasonably safe to keep in a tank with fishes. Due to their size of up to one meter in length they should only be kept in a very large aquarium. Being very reclusive they require deep hiding places where the whole body can be hidden. Because of their size rocks should be well anchored to prevent them from pushing them over.
They are easy to feed and are hardy. They can also go for a considerable period of time without eating. With their blunt grinding teeth, crab and shrimp are good foods for them. Meaty foods such as fish flesh and squid will also be eaten.
ZEBRA MORAY EEL CLASSIFICATION
- The Reef Guide fishes, corals, nudibranchs & other invertebrates: East and South Coasts of Southern Africa by Dennis King & Valda Fraser