|The ribbon moray, Rhinomuraena quaesita, a rather unusual moray with atypical, brilliant coloration.|
Don't try the trick shown in the video above on your own! Hand feeding of morays is an activity frequently used by diving companies to attract tourists. But Morays have poor eyesight and locate prey mainly via their acute sense of smell. When hand fed they have trouble telling small fish from finger. So they may remove a few of yours. In some countries hand feeding of morays has been banned.
It is true, however, that morays are ordinarily shy and relatively harmless unless their burrows are invaded, in which case they can become highly aggressive. Many divers have drowned with their hand clamped in the mouth of a moray who probably just saw the situation as a matter of defending its home. Thus, they have a very bad reputation, that's really unwarranted, at least on the basis of temperament.
The moray's recurved teeth and powerful jaw mechanism also make for an atrocious bite, which does not release even when the eel is killed. Most morays are not venomous, but some evidence suggests that certain types are, though more research on this point is needed.
Morays feed mainly on small fish, octopi, cephalopods and crustaceans. The largest moray eel is the giant moray (Gymnothorax javanicus), which reaches a weight of 70 lbs (~30 kg) and a length of 10 ft. (~3 m). The smallest is Snyder's moray (Anarchias leucurus), which is only 4.5 in (11.5 cm) long. The longest is the slender giant moray (Strophidon sathete), which gets up to a length of about 13 ft (4 m). Morays gape their mouths, not out of agression, but because their gills are small and located far back on their flanks, which makes respiration more difficult than in most other fish.
Although two types of moray, the freshwater moray (Gymnothorax polyuranodon) and the pink-lipped moray eel (Echidna rhodochilus), live in freshwater, most reside in salt or brackish environments. Living at depths of up to several hundred meters, they occur primarily in tropical or subtropical regions, especially on coral reefs, but some are also found in temperate waters.
Morays are unusual in that they have pharyngeal jaws, a second set of jaws, which they shoot forward to grasp a food item and then retract to draw it deep into their maw before clamping down with their powerful ordinary jaws (see picture below). Morays usually lie in wait and ambush their prey with a sudden lunge.Image: Wikimedia