Ciguatoxic fishes

Sieve Moray, Gymnothorax cribroris (Photo: Ian Banks). Chinamanfish, Symphorus nematophorus – juvenile (Photo: Ian Banks). Chinamanfish, Symphorus nematophorus – adult (Photo: Ian Banks). Paddletail, Lutjanus gibbus closeup (Photo: Ian Banks). Paddletail, Lutjanus gibbus in school (Photo: Ian Banks). Red Bass, Lutjanus bohar. Pickhandle Barracuda, Sphyraena jello (Photo: Ian Banks).Ciguatera poisoning generally occurs several hours after eating reef fishes from tropical and subtropical regions. It is most common in relatively large specimens of a small group of higher order predatory species, but numerous other reef fish species have been involved on a more occasional basis. Its incidence is highly unpredictable within individuals of a particular species and between fish from different locations.

Fishes known to often have ciguatoxin in their flesh include:

  • moray eels (Gymnothorax species)
  • Chinamanfish (Symphorus nematophorus)
  • Paddletail (Lutjanus gibbus)
  • Red Bass (Lutjanus bohar)
  • barracudas (Sphyraena species)

These species are either ‘no take’ under Fisheries regulations, or not accepted for sale by fish marketing bodies, so are rarely eaten in Australia.

More occasional problems have been noted for coral trouts (Plectropomus species), rock cods (Epinephelus species), emperors (Lethrinus species), tropical snappers (Lutjanus species) and Spanish Mackerel (Scomberomorus commerson), all of which are very popular commercial and recreational angling species. These species are implicated in a large proportion of the reported cases of ciguatera poisoning, however the prevalence of ciguatoxin among these groups as a whole is extremely low in Australia. A single large fish can cause an ‘outbreak’ of poisoning, as portions of one fish can potentially be sold to and eaten by many different consumers.

There is no reliable method of determining in advance whether a fish contains ciguatoxin. However, high risk species should not be eaten, large specimens of lower risk species should be avoided, and it is best for only modest amounts of any tropical reef fish to be eaten, at least until it is confirmed to be safe. If large or suspect fish are to be eaten, a useful approach is for an adult within a group to eat only a very small portion in the first instance, with no follow up meals of the same fish until the following day. If no symptoms ensue, the fish is most likely fit for general consumption.

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