Terpenoids are commonly found in alcyonacean soft corals of the Great Barrier Reef (Coelenterata, Octocorallia), but they are highly variable in their distribution within this order. Such secondary metabolites in these organisms vary widely in type, concentration, and function. Thus far, they have been found to play roles in predator defense, competitor defense, anti-fouling, and reproduction. The effectiveness of compounds derived from individual species also varies widely with respect to interactions with other members of the community. These chemical characters function in concert with other morphological, physiological, behavioral, or developmental adaptations that have similar functions. Integration of these adaptations is highly species-specific. The multiple functions of terpenoid compounds and the high degree of species specificity in their ecological roles greatly reduces the ability to predict either the presence or absence of a terpenoid from other related characters. In addition, simple indicators of terpenoid function appear not to exist. If such indicators do exist, they are more likely to be found at higher levels of taxonomic resolution (within families or genera).