Siganus nebulosus (Non Quoy & Gaimard, 1825)
dusky rabbitfish, happy moments, black trevally
Siganus nebulosus, dusky rabbitfish

family Siganidae - rabbitfishes

The Dusky Rabbitfish, Siganus nebulosus, has unusual colour patterns, can switch almost instantaneously from the mottled camouflage colours of the right picture to the small even spots of the left picture.
This family of plant feeders (Siganidae) are known as rabbitfishes, because of the shape of their snout or as spinefeet because of the unusual arrangement of pelvic fin spines.
All dorsal, anal and pelvic fin spines are grooved and venomous. They can inflict painful wounds, hence the ironic common name "Happy Moments".

Distribution =   central east and west coasts of Australia
Max size =   30cms