Although most species in the Red Sea pose no threat to humans, there are a few notable exceptions.
Biting and wounding fish
Stinging and venomous fish
Poisonous fish
Ciguatera poison
Ciguatera poisoning is a danger posed by fish at the top of the food chain, in particular the Twinspot snapper and Giant moray. These fish accumulate a toxin produced by a dinoflagellate which is eaten by their prey species. Ciguatera poisoning can be fatal.