Related FAQs: Moray Eels, Morays 2, Moray Eels 3, Moray Identification, Moray IDs 2, Moray Selection, Moray Behavior, Moray Compatibility,  Moray Compatibility 2, Moray Compatibility 3, Moray Compatibility 4, & Moray Systems, Moray Feeding, Moray Disease, Moray Disease 2, Morays and other Eels & Crypt, Moray Reproduction, Freshwater Moray Eels, Zebra Moray Eels, Snowflake Morays, Other Marine Eels,  Conger Eels,  Freshwater Moray Eels, Related Articles: The Zebra Moray (Gymnomuraena zebra), The "Freshwater" Moray Eels, Freshwater Moray Eels by Marco Lichtenberger, Non-Moray Marine Eels, Snake & Worm Eels, Dangerous Marine Animals The What, Where, Avoiding and Otherwise Dealing with Biological Stinger, Biters, Pokers as a Diver. Moray Eels: Look For, Don’t Feed or Touch

by Robert Fenner

 

Of all the anomalous behavior I’ve experienced amongst divers; the haphazard placement of their hands, even petting and feeding of Moray Eels strikes me as the most foolhardy. These animals are NOT pets; but wild animals… that have markedly poor eyesight and the capacity for doing tremendous biting damage and notable secondary infection. Not to scare you out of enjoying encounters with these fishes; it is my fervent hope only to encourage your caution in approaching them.

Look; but don’t touch. Here is a skeletal mount of a Gymnothorax species skull at Aquarium Adventure, Camden, New Jersey, showing the formidable teeth and structure that allows for the tremendous biting and locking of jaws of the Moray family.

 

 What are Morays?

Morays are true eels, members of the biological taxon, Order Anquilliformes. There are other “Eel” families and eel-like fishes; usually judged simply on the basis of having many head lengths into their body lengths in proportion or locomoting via throwing their bodies into sigmoidal curves. The Moray family, Muraenidae comprises some two hundred species divided into sixteen genera. They occur in all oceans (and there are a few freshwater species) in tropical to temperate shallows to a few hundred meter depths. Surprising to some folks is just how numerous these usually shy, reclusive fishes are. In Hawaii, the thirty some species of “puhi” make up more than half of all fish biomass on nearshore rocky reefs. I have even been shocked at times when out during biological surveys, at just how many Morays “float out” when an area is sampled.

 Some are under a foot in length, though most are a few feet, and a few get to about three meters long.  

Small and large species; a Dwarf or Golden Moray, Gymnothorax melatremus, maxes out at a foot in length (here in S. Leyte, P.I.); at the other end of the scale, the Java Moray, G. javanicus gets to about three meters in length and the thickness of your leg. Here a large one is getting a bit of gill cleaning by a Labroides wrasse in Moorea, French Polynesia.

            All Moray Eels have large mouths and numerous teeth, though some species teeth are rounded knobs, a modification useful to them as crab and shrimp eaters. Most Morays are piscivorous however and their jaws bear sharp, backward curving conical teeth; useful for grabbing and tearing prey, and directing it back to the throat.

A Gymnomuraena zebra out in Kona, HI. A bonafide crab eater. And a more typical piscivorous Moray, a Japanese Enchelycore pardalis, the Dragon Moray.

 

            Look ma, no fins! Look closely at a Moray, notice anything? Yes; they lack pectoral, pelvic and caudal fins! Look more closely; they also are scale-less, smooth-bodied fishes. Though very bony, and at times, places vectors of ciguatera fish poisoning Morays are consumed in large numbers by humans around the world.

Examples (to avoid):

Actually, all Muraenids should be looked out for. They all have celebratedly poor vision and will bite if frightened. Here is another Java Moray (in Northern Sulawesi) with a not uncommon physical injury. These fishes at times will dart out of their lairs or thrash themselves on hard surfaces seeking prey. Being tubular shaped, elongate and finless helps in diving into caves for crustaceans, fishes and cephalopods but the lack of scales can easily result in mechanical injury.

 

By Day or Night:

            Morays for the most part are nocturnal animals; aquarium-desirable species are mostly collected at night time; though they do make day-time appearances.  

Secretive by day, Morays have poor vision but keen olfactory/gustatory sense. Other good reasons to NOT offer them food by hand. This couple of Green (California) Morays (Gymnothorax mordax…. The genus meaning “naked chest” in reference to their lack of pectoral and pelvic fins, and mordax from the Greek “biting”) have been trained to come out to entertain tourists at UCSD, Scripps Institute of Oceanography’s Birch Aquarium in San Diego, CA.

 

            Though they look menacing, Morays keep their mouths open principally to aid in aerating their gills, pulling water into the mouth via buccal suction, passing it over their gills and out the small gill opening on either side of their heads.

Avoiding Troubles:

             Staying out of trouble is easy to do if you adhere to good diving practices of NOT TOUCHING anything while in the water including practicing good buoyancy control. It is exceedingly rare that a Moray will swim out of cover expressly to approach or bite a diver. If you see one out and about, do keep your eyes on it, and if it approaches you, hold your arms and legs close to your body.

            If for whatever reason you find yourself poking about or worse, lifting rocks on the bottom, be aware of the imminent possibility that you may get bitten, stung, or badly scratched in the process. Gloves can help, though some Morays can bite and hold more strongly than a human can resist. On this same note, and though it may read as impossible to comply, the best thing to do if bitten is to remain calm and NOT PULL BACK from the animal; too-likely resulting in further damage. Almost always a Moray will quickly release a non-struggling body part.

 

Treatments: Physical and Biological

            Any Moray bite should be taken very seriously. The microbes associated with their mouths have been known to cause dangerous infection. WASH the area thoroughly. Are Moray bites toxic? This is a still-debated point, though it is scientifically known that some do excrete toxins in their body slime (crinotoxins). Some of these studied toxins cause red blood cells to clump (hemaglutinin), and others to split RBCs (hemolytic). Can these toxins be transferred into bites? The bites DO HURT as if this were so.

            Oh, and some of these toxins are glycoproteins; so there may be allergic reactions to contend with as well.

            Secondary infections are commonly associated with Moray bites. Think of all the neat cleaner shrimp and fish photos you’ve seen with Morays in them. Their mouths are not clean, and do transfer microbes when they bite; among them septicemia causing Vibrio and ever-present Pseudomonas.

Even for small bites that result in physical damage and toxic exposures, sources encourage the immersion of the affected area in very warm water for a few tens of minutes for denaturing probable protein toxins as well as hopefully killing harmful microbes. Disinfect the area and if swelling, redness or pain persists, DO seek medical help. Bacteria in the blood (septicemia) can result in hospital stay and the need for aggressive, monitored antibiotic administration.

Larger bites with tissue damage, blood loss, call for steps to alleviate bleeding and immediate medical care.

 

Cloze:

            So; as with all dangerous marine animals; forewarned is fore-armed: be aware of, and avoid coming in physical contact with too-spiny and toxic sea urchins. This is easily done given good buoyancy control, awareness of your surroundings; and the usual good placement of your hands and body en toto. Should you get barely spined unintentionally there is likely little you can and should do other than ameliorative analgesic action. Too many, too deep spines breaking off in you or too extreme effects of duration call for prompt medical attention. Morays aren’t vicious fishes, and are undeserving of such a label; however they can be dangerous if provoked, or startled.