This monster started to feed within a few minutes of sharing the inspection tray with its victims. This nymph is a voracious predator of small invertebrates and has even been noted for feeding on small fish and salmonid alevins. The niche it fills in fast water is equivalent to the Dragonfly nymphs that inhabit slower water.
nymphs are easily distinguished from other western perlids by the presence of anal gills
(obfuscated by algae in the tray) in combination with an hour glass shaped pale mark on the front of their heads.