This is Archipielago de los Jardines de la Reina, an underwater park established in 1996 to protect the reef and it's inhabitants. The result is many different species of fish that are allowed to grow to a great size, specifically the goliath grouper - which is extinct in much of the Caribbean. There is also a prevalence of sharks, which were with us on almost every dive. Where the reef in many parts of the world is dying, this park demonstrates how corals and fish can thrive.
This video depicts a dive trip organized with Denver Divers, through Ocean Doctor and Avalon in February, 2015.