Bileiydhoo Thila is a 227-hectare thila on the northern side of the Ihavandhippolhu Atoll and is known for being one of the most popular thilas in the Northern Maldives among divers. This thila is home to a variety of species, and is a famous dive site in the Maldives. It is known for being an 'aquarium' where the most number of underwater species in one area is observed. Important species such as rays, Napolean wrasses, sharks, and different types of turtles frequent this thila. A manta cleaning station also exists in this thila. 20 meters below the sea level, a vibrant ecosystem of species can be found, and huge caves are found further below. These caves are occupied by a great number of nurse sharks (nidhanmiyaru). Moreover, rays and dogtooth tuna (voshimas) are also found in the 'Top Reef' of this thila.