Ray

The ray is a flat brown fish found in the ocean. The fish is quite large, and it has a huge shadow. It appears all the time. It is a quite expensive fish, selling for 3,000 Bells. The ACCF caption reads: "Freshwater types of these relatives of sharks are popular pets." When placed in the museum, like all other salt-water fish, except for the small ones, appears in the very back tank.

Further information
The Animal Crossing ray is actually a sting ray. You can tell because you can see the stinger above the tail. Its real name is the Southern stingray. It can be found in the southern Atlantic Ocean, around the Carribean and in the Gulf of Mexico.