Hearing sensitivity and sound characteristics of poikilothermic animals are influenced by ambient temperature. The present study investigates the influence of temperature on the hearing ability and on sound characteristics in the neotropical Raphael catfish Platydoras costatus. Using the auditory evoked potential (AEP) recording technique, the hearing thresholds of eight specimens were tested at six different frequencies from 100 to 4000 Hz. The temporal resolution was determined by analyzing the minimum resolvable click period (0.3 - 5 ms). Hearing sensitivity and sound production were measured after acclimation to 22 °C followed by acclimation to 30 °C for at least three weeks each. Auditory sensitivity increased from 1 to 4 kHz with rising temperature, whereas the temporal resolution showed no change. Catfishes produce stridulation sound by rubbing the pectoral spines in the shoulder girdle during abduction and adduction of pectoral fins. Distress calls were recorded when fish were handheld. The stridulation sounds produced during pectoral fin spine abduction and adduction became shorter at the higher temperature. Maximum and minimum pulse period as well as pulse number did not change with temperature, whereas the dominant frequency of sounds was higher at the higher temperature. Our data indicate that constraints imposed on hearing sensitivity at different temperatures cannot be compensated even by longer acclimation. As sound characteristics also change with temperature, we suggest that the ambient temperature directly affects acoustic communication in the neotropical catfish P. costatus.