The highest incidence of ciguatera occurs in warm-water
coral reef fish, especially in the Caribbean and Pacific, usually
between 35° north and 35° south latitude. It’s caused
by a microscopic alga that accumulates in the flesh of
larger species (two kilograms, or five to six pounds), such
as barracuda, snapper, jacks and groupers and has been
found in 425 species. The majority of coral reefs are not
ciguatoxic. Outbreaks of ciguatera are limited in distribution
and time and are usually very localized.
Seek early medical attention if you suspect you have
  ciguatera. You can call the Ciguatera Hotline at (305) 661-
  0774 or DAN’s Diving Emergency Hotline at (919) 684-
  8111 for advice. 
Nevertheless, the Centers for Disease Control and
  Prevention says: “Unfortunately, there is no single specific
  remedy for the treatment of ciguatera fish poisoning.
  The most successful management of the disease has been
  accomplished by supportive and symptomatic treatment
  such as induced vomiting.” Include oral antihistamines in
  your first aid kit, as these are likely to help relieve the debilitating
  itching. Don’t expect your resort to be prepared.  
For information, go to www.cdc.gov/nceh/ciguatera.
  www.rehablink.com/ciguatera has helpful advice for divers.