Hi dinus lextopus

If your leader is long enough and your presentation is good the fish shouldn't really see the line when dry fly fishing.

With sinking lines some prefer a clear line, though most seem to be dark colours.

Some prefer a Hi Viz colour to see the line better especially at distance.

Some argue the fish only see a dark line when looking up so the colour doesn't matter.

Some say a bright colour spooks the fish.

Having fished for very spooky fish in clear waters in NZ and UK with Hi Viz lines and catching fish, it's my experience that presentation is more important.

It might help having a dull sombre colour line, but not when constantly casting over the fish and splashing it down on the water.

Not sure there is any actual proof that fish see colours, but they do seem to prefer different coloured flies sometimes.

 

Well said Wizard,sum's it up perfectly.

Jim