The more stirring the better: cichlid fishes associate with foraging potamotrygonid rays

One hunting tactic of freshwater rays (Potamotrygonidae), termed undulate the disc and stir substrate, is here reported to attract cichlids at two sites in the upper Parana River. The ray species involved in such association are Potamotrygon falkneri and P. motoro, whose activity attract four cichlid species, namely Crenicichla britskii, Satanoperca pappaterra, Cichla kelberi, and Geophagus proximus, the two latter non-native species to the study area. The cichlids approach a ray when it begins to stir the substrate and form sediment clouds, and remain close to the ray during this activity only. The association is here regarded as following behavior even if very transient.