A Multi-Component Species Identifying Pheromone in the Goldfish

Although it has been established that sexually-immature goldfish and their relatives recognize members of their own species by using chemicals that they release, the identity of this cue(s) and whether it might be produced and used by other life stages is not yet known. To address this question, this study tested the behavioral responses of sexually immature and mature goldfish to each other's body washings, their sensitivity to this cue, the role of the olfactory sense in detecting it, and whether it is comprised of either polar and/or non-polar compounds. Tests that used two-choice mazes discovered that juvenile, immature, mature male, and mature female goldfish all release and respond to a common chemical cue(s). Dilution studies next demonstrated that this cue is active when diluted over 10 times and thus capable of functioning as a short range attractant/identifier. Olfactory occlusion demonstrated that it is detected by the olfactory sense. Finally, chemical fractionation demonstrated that it is comprised of both polar and non-polar components but likely does not include bile acids. Together, these results suggest that all life stages of goldfish use a complex multicomponent pheromonal odor to discern species identity, and that this odor has the potential to function with hormonal metabolites to identify sexual condition in behaviorally active fish of many species.