While diving this morning, I came across a kelp greenling couple while they were courting (Hexagrammos decagrammus).
In addition to being fascinated by the courtship behaviour, I was struck by the intense colouration, especially of the courting male.
Mature male and female kelp greenlings look very different but I had never fully realized how the males’ gender specific colour intensifies during courtship. Their bodies become much paler while the heads remain dark blue.
This 1.5 minute video shows the courtship behaviour. See below for an image of eyed kelp greenling eggs.