The gut contents and the liver of a parrotfish Scarus gibbus contained ciguatoxin but not scaritoxin in spite of the fact that the latter toxin is dominant in the flesh. Absence of scari toxin in the diet suggested the possibility that the toxin was produced by the fish from a precursor in the diet. The conversion of the precursor, however, will not take place in the liver.
The gut contents contained maitotoxin and acetone soluble toxin(s) besides ciguatoxin. This newly found acetone soluble toxin was assumed to be a basic compound of small molecular size having strong paralytic action.
Algae content in the gut contents of the parrotfish was estimated to be very low on the basis of chlorophyll concentration. It was concluded that algae are not the organisms which produce the toxin(s).