Lovely treatment! That fish looks lethal even in death.
Focal length can also become habit: throughout my fashion years, despite having lenses from 24mm to 500mm, I would guess that my two most-used lenses for Nikon were the 35mm and 135mm, the former for full-length and even half-length model shots, the resulting distortion actually being a feature, which currently makes me scratch my head a little, the longer lens reserved mostly for headshots. That work was predominantly in black/white. My 50mm was practically virgin right until I disposed of all my 135 format equipment one mad day.
When I switched to calendars, I began to find myself slightly more fond of long lenses. The calendars were mostly colour, so perhaps the genre does really impact the choices made, for me, at any rate.
Today, the majority of the time I have the 50mm on my old cut-frame D200 (equiv. 75mm on FF) which seems to combine pretty well with my present way of thinking... that said, I wonder which the chicken and which the egg!
Rob