I recently dove with an instructor, who had a VERY BRIGHT fins and wetsuit in a murky lake. While that seemed wise even before we jumped in the water, after the first dive I was VERY thankful.
I did notice I often had trouble distinguishing which person was my dive-buddy underwater. I finally remembered my hood was blue underneath, so I decided to wear it inside-out & set my tank-light to blue since everyone else had red or white.
Since I'm working on a new harness, I decided to go with a relatively bright color that I find palatable & I'll probably attach some similarly-colored fabric to my wetsuit as well. I'm currently trying to find some decent inexpensive fabric (prefer stretchy) that is highly reflective, so I can sew or glue strips of it various places. I'm not necessarily trying to look like a glowing nuclear monster, but making myself more visible to other divers and boats is probably a good thing.
I also have a hot pink mask strap cover that is very visible underwater.