El Bajo del Muerto

A submerged pinnacle southeast of Isla Muertos tops out at 12 m and plunges to 35 m on all sides, its walls thick with black coral fans and schooling surgeonfish. This is the primary manta ray cleaning station in the Bat Islands complex — Pacific manta rays (Mobula birostris) hover motionless at 10 to 18 m while cleaner wrasse work their gill plates, often ignoring hovering divers entirely. Visits from November through May yield the highest manta encounter rates. Bull sharks patrol the deeper sand channel at 30 m during the rainy season, and large schools of rainbow runner and yellowfin tuna sweep through the blue water regularly.