River swale barbel. This year we are focusing some of our time on the mighty river swale. These fish often sift through the substrate at the bottom of rivers using their barbels to detect the movements and scents of insect larvae, crustaceans, and other small invertebrates. This specialized feeding behavior allows them to find food even in conditions where sight alone would be insufficient. #freshwaterfish #barbel #nature #rivers #underwater | Beneath British Waters