One would have to assume that the red tail acted (or acts) as an attractor, an ‘excitor’ to the trout. But, you would be hard pressed to find many fly tiers that use red in their patterns these days. I am not talking about Steelhead patterns, but rather the trout patterns. I think red tails are perhaps worth a try and purple, hot green, blue, orange…. Water clarity and depth can influence the color spectrum and visibility. Experiment with some colors.
SwittersB & Exploring 
I like to invite you to visit http://www.andrestouceda.com/contenidos/concurso2011/EN/concurso.php ,
The International realistic fishing flies contest – The First contest by internet – its free and its for a good cause – the protection of rivers.
follow de link for more information
note: You have a very nice web site. I like it – Congratulations
Best regards
Diego Sotelo – VagaLume Studios
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Yes, I think you will see a decided variety of wet flies with a red tail or tag in the UK.
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I like to tie peacock and grouse wet flies with a red hackle fiber tail. Whether it makes them better, who knows? But they catch fish, that I do know.
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