Nurse Shark (Nebrius ferrugineus)
You will see quite a few sharks here at Under Water World. If you've spotted the relatively harmless Nurse Shark, chances are it's moving very slowly or maybe even resting on the bottom. Unlike many of the other sharks, the Nurse Shark doesn't move around a lot. Many sharks must swim constantly in order to force water over their gills, but the nurse shark doesn't have that problem.

Blacktip Reef Sharks (Carcharhinus melanopterus)
This relatively common Indo-Pacific Reef Shark is very active and occurs singly or in small groups. Unlike the Nurse Shark, this sleek creature must swim constantly in order to breathe. The Blacktip Reef Sharks feed on small fish and invertebrates and are in turn preyed on by larger sharks and man. Interestingly, these sharks can now also be found in the Eastern Mediterranean, apparently having migrated through the Suez Canal.

Giant Grouper (Epinephelus lanceolatus)
This giant is the largest reef-dwelling bony fish. The Giant Grouper is solitary and can be found inhabiting lagoons and seaward reefs, up to a depth of at least 50 m. Large individuals usually have a home wreck or cave that they frequent. These giants feed on crustaceans, especially spiny lobster, fishes, small sea turtles and even small sharks - all swallowed whole! Even though large specimens may be ciguatoxic and have inferior quality flesh, they have been the target of spear fishermen. It takes decades for the grouper to reach adulthood and juveniles are hard to find, and accordingly there is little chance of large individuals reappearing in unprotected areas.

Gray Reef Shark (Carcharhinus amblyrhnchos)
You are probably grateful for that wall between you and the Gray Reef Shark. But how dangerous is this shark? Should we be afraid of it? Although the Gray Reef Shark's curiosity often gets mistaken for aggression, chances of attack are very low. To give you an idea, in the last 20 years, only five shark attacks were reported off Guam, all non-fatal. Further, all of these were probably cases of mistaken identity, where the shark mistook an early-morning fisherman for its prey. This is not to suggest that you should go out of your way to provoke a Gray Reef Shark, but as is the case with most potentially dangerous animals, if you leave them alone, they'll return the favor.

White Tail Whip Ray (Himantura granulata)
The graceful ballet of a ray gliding in the water is an amazing sight. They can't glide for long since they lack the swim bladder of most bony fishes and as such they are not able to achieve neutral buoyancy. Like their shark cousins, if they are not actively swimming, they will sink to the bottom. Rays are well-built for lying on the bottom where they feed on slow moving, benthic prey like invertebrates and small fishes.

Whitetip Reef Shark (Triaenodon obesus)
This small, slender shark can be found, usually resting, on the bottom under overhanging ledges or in caves. This Reef Shark seldom comes to the surface and in fact is capable of sitting motionless for long periods in the water. The White Tip Reef Sharks are live-bearers.

Shovel Nose Guitarfish (Rhinobatus typos)
It's a shark! It's a ray! No, it's the Shovel Nose Guitarfish, which looks a little like both. A Shovelnose Guitarfish has some of the characteristics of both a shark and a ray. It has a long, thick body like a shark. It gives birth to its young, fully formed, like both the shark and the ray. It doesn't have a shark's pointed head and sharp teeth, but it does have the spread-out head, small mouth and flattened teeth of a ray. Though you might find a Shovel Nose Guitarfish around Guam, you'd be very lucky, as they are rare here. You've got a better chance of spotting them off the shores of Japan or Australia.

FanTail Ray (Pastinachus sephen)
Looking at the FanTail Ray, notice the holes behind the eyes. These are the nostrils - sort of! Normally when a fish breathes, it sucks in water through its mouth, passes it over the gills -where the oxygen is extracted - and then expels it through the gill slits. However, a ray lives on the bottom of the sea, and its mouth is on the underside of its body. Accordingly, if it tried to take in water through its mouth, it would end up with gills full of mud. To solve this problem, rays have a little hole behind each eye, called a spiracle, where water can enter the throat and gill cavity.

Zebra / Leopard Shark (Stegostoma fasciatum)
These lovely creatures, are commonly found on tropical coral reefs. There is no mistaking the Zebra Sharks with their long broad tails and distinctive coloring. Juveniles have stripes that gradually fade into the spots of the adult. Because of the spots of the adult, they are also known as leopard sharks. This shark has small barbels on its snout, small eyes and mouth. They also have tiny spiracles behind the eyes, indicating they are bottom-dwelling. Divers occasionally find a shark resting on the bottom, propped up on its pectoral fins with its mouth, open facing into the current, waiting for food.

Giant Spider Crab (Macrocheira kaempferia)
This is the world's largest crustacean and can measure up to 26.5ft (8m) between the tips of its legs when splayed out! Giant Spider Crabs have a restricted distribution off the southeast coast of Japan. They live on sandy or muddy bottoms between 100-165ft (30-50m) in depth, in slow-moving water. Although little is known of their life history, we do know they feed on prey that includes other crustaceans as well as echinoderms, worms, and molluscs.

Lionfish (Pterois volitans)
*Clearfin lionfish: (Pterois radiata)
The long graceful fins on these spectacular fishes carry extremely venomous spines and can inflict a painful wound. Lionfish are slow-moving and spend much of their time in caves or under rock ledges. These popular pet store fishes use their large pectoral fins to herd prey into a corner for easier capture. Lionfishes feed primarily on small fishes and shrimp, swallowing them whole.

Pufferfish Blackspotted (Arothron nigropunctatus);
Map puffer (Arothron mappa)
As their name imply, pufferfish have the ability to inflate themselves when threatened, making it difficult for predators to swallow them. Even if a predator managed to gulp one of these prickly guys down, it would be the last meal they ever ate. Pufferfish are highly toxic. There are enough toxins in one pufferfish to kill over thirty people. Despite this fact, they are considered a delicacy in Japan. Specially certified chefs prepare 'fugu', made from this deadly fish.