Chinese trumpetfish (Aulostomus chinesis) feeding on a milletseed butterflyfish (Chaetodon miliaris).  While patiently stalking a school of reef fishes that was preoccupied devouring fish eggs, this trumpetfish suddenly shot its mouth forward and sucked in a large milletseed butterflyfish. Trumpetfish have quite the mouth gape and can increase the volume of their mouth by more than 15x to capture prey! Hawaii.

Photos about trumpetfishes (Aulostomidae):