These fishes usually have sensorial appendices and inferior protractile mouths (Chao & Musick, 1977; Gerking, 1994), and prey on benthic invertebrates near or on the bottom, burying the mouth into the substrate and swallowing part of the sediment (Hobson & Chess, 1986; Sazima, 1986; Soares et al., 1993; Edgar & Shaw, 1995). Differences in behaviour, habitat and time of feeding, as well as kind and size of prey, may reduce dietary overlap among benthivorous fishes (Hobson & Chess, 1986; McCormick, 1995; Platell et al., 1998).