Alarm response of Arius felis to chemical stimuli from injured conspecifics

Abstract

The hardhead catfish (Arius felis) showed increased activity when subjected to water containing chemical cues of injured conspecifics. This response was similar to the visually stimulated response to a model of a predatory fish. Arius felis also responded to chemical cues of injured sailfin mollies (Poecilia latipinna) with increased activity, but this was less than in response to conspecific chemical cues. A histological examination of Arius felis epidermis revealed that the alarm substance cells of marine catfish are similar to those of freshwater catfish. Responses to odors of injured individuals is common among ostariophysans, which are mostly freshwater fishes. This is the first demonstration of an alarm reaction in a marine ostariophysan.