I dive in Hawaii where ciguatera is a problem as well. The crapy thing is that there is no real easy or 100 percent fool-proof way to tell if a fish has the ciguatera toxin. The test kits are ok but will often give false posotives if the testing situations arnt perfect. They dont have much of a shelf life so its hard to find a shop that even carries them. Ordering online is an option but then again if you keep it for to long its no good.
The fly thing is just a rumor. The cuguatera toxin has no taste or odor, it cant be cooked off, and has some pretty gnarly effects.
My only advice to you would be to talk to other local fisherman, divers and find out what species are more likely to have the toxin. Then just try to avoid those particular fish. Another factor is size and age. The older and bigger the fish the higher the concentration of the toxin can be.
In hawaii we have many species that are known to have the toxin. We also have a local fishing news which publishes all reported cases of ciguatera in the state, which fish it came from, which island, and which particular area. Some areas are worse than others, some island are worse than others. I read the paper each month and take note of new cases. For the most part its all the usual suspects... surgeonfish, peacock groupers, amber jacks (this one sucks, ive had up to 50 or 60 pounders come right up to me but I wont take the shot because they will almost guarantee have the toxin, Ive heard they are great eating too), large ulua (giant trevally),I dont hear of too many cases coming from parrot fish, or atleast the ones we have here.
In short stay away from the usual suspects and the rest will still be a gamble.
Or you could always give a fillet to your neighbor and give it a day to see how he reacts
the side effects usually take effect within 24 to 48 hours.
Good Luck
