Since writing my article titled Unusual Behaviour by Senator Fish, Pictilabrus laticlavius, I have observed similar Senator Fish behaviour at Rapid Bay jetty.
In March 2015, I had witnessed some unusual behaviour by Senator Fish at Rapid Bay jetty. The unusual behaviour that I witnessed by them was that many of them were often rubbing their bodies in the substrate. (There seemed to be more male Senator Fish than usual swimming around. They weren’t swimming in schools or large groups, but there did seem to be more than what I would normally expect to see around during a dive anywhere.)
I only recall seeing the one male Senator Fish during my dive at Rapid Bay jetty on 23rd January 2016. It was performing the very same ritual as the many males observed in March 2015, rubbing its body in the substrate.
I took this series of photographs of the fish at the time (Click on each photo to view a larger image): –
The seagrass cover seems to be important to the activity of the male Senator Fish. Is it preparing a nest for a female to lay eggs perhaps?