The Shark Group is the group of five fish, first introduced in Animal Crossing: Wild World, that have a fin when seen in the water. They include the hammerhead shark, the shark (likely a great white shark), the ocean sunfish, the saw shark, and the whale shark. Even though the ocean sunfish is not a shark, it is still a member of this group as it has a "huge w/ fin" shadow. These fish can be found only in the ocean. They are often found near rocky outcrops on the side of the ocean.
The ocean sunfish is different from the other sharks because it is the only shark to appear from 4 A.M. to 9 P.M. This means it is the most common shark since it is the only shark which can be caught during the day.