El Tanque

A perfectly circular cenote where fresh groundwater meets salt water at a sharp halocline that shimmers like liquid mercury — the freshwater lens above 8 m is so clear it distorts depth perception while the saltwater below holds a different world of cave-adapted crustaceans and sleeping reef fish. The cenote sits just metres from the Caribbean shoreline, connected by underwater passages that allow small fish and invertebrates to move freely between habitats. Night dives here reveal ruby red shrimp, flattened crabs, and the occasional blind cave fish hovering motionless in the crystal water column.