Most of what you see of a mottled moray is the head. It extends from a crevice at the edge of your torchlight, jaw working slightly, white spots vivid against the dark brown body, and the rest of the animal remains inside the rock in a quantity that is difficult to estimate. There could be a lot of moray back there. The head alone does not give a reliable indication of how much. Gymnothorax prionodon is known in New Zealand simply as the mottled moray, and in Australia as the Australian mottled moray, a distinction that serves mainly to clarify geography. It is a large eel, commonly reaching 80 centimetres and occasionally 150, with a muscular, laterally compressed body covered in a pattern of clear white spots on dark brown that provides effective camouflage against coralline rock. The jaws are long and armed with the serrated teeth common to the family: designed for gripping rather than crushing, because a moray that bites something intends to hold it. Those teeth are also visible when the eel is doing nothing at all, which creates a misleading impression of constant intent. Like all morays it hunts primarily by smell. The nostrils are tubular, protruding from the snout to create directional sensitivity, and a moray following a scent trail through dark water is doing something closer to precision navigation than casual foraging. The mouth opens and closes rhythmically while the eel rests, which divers commonly interpret as menace but is simply the mechanism for pumping water across the gills. It is breathing. The expression it gives while doing so is a design constraint, not a warning. In New Zealand the mottled moray is most reliably found at the Poor Knights Islands and the Cavalli Islands in Northland, where the rocky reef structure provides the crevices and ledges it requires. It is not commonly encountered further south. Individuals appear site-faithful, returning to the same holes across multiple seasons. Territorial disputes between morays are occasionally observed and are brief, decisive, and loud in the accounts of divers who have witnessed them from a safe distance. It will bite if provoked, and it does so quickly. Divers who have handled morays for photographs or reached into crevices without looking have reported this. The eel's disposition is not aggressive by default. Its response to being grabbed is unambiguous and does not come with a warning. Both of these things can be true simultaneously.