I believe in imitations when fishing for fish that actually eat. I do use provocative flies, and I use strange combinations like a pink gammarus (which looks nothing like a gammarus). Sometimes visibility can take over as the primary reason for choosing a fly. In murky water it's more important that the fish sees your fly than the fly looks like the real thing.
When fishing for sea trout and salmon in the rivers, this is something I often think about when the water's not clear. In better conditions, I find it's sometimes just as important that the fish only sees the fly just before it's swung past it's nose - to give the fish less time to react. This is an old theory, which sometimes seems to work (even in murky water - go figure...).
In fly visibility contrast is important, I think. This can be achieved with built-in contrast in the fly (black and yellow, for instance), or it can be done by letting the fly itself contrast as much with it's surroundings as possible. Contrast can also be a more arbitrary matter - which sometimes really makes a difference. Contrast in this case can be presenting fish with styles/colors/sizes of fly they've not seen before.
This is what I had in mind a few months ago when I started thinking about white flies for pike. I'm sure they can be thought of as imitations (probably not far from how a roach looks under water). But my main reason was that white pike flies aren't that common, and I've seen how heavily fished pike water can turn into almost pristine fisheries when using something the fish aren't used to seeing.
I tied some white pike flies for my recent trip to Rügen (and they failed completely :-). These were tied on hooks, and I've been looking for a good style to convert them to tubes for a while. I saw a really nice grey/white/red tube fly by Kenneth Giese Hejnfledt (check out his Instagram here - he ties fantastic pike flies). I took that style, altered it just a little bit and tied the White Walker.
This fly I believe a lot in. Almost every material is fluorescent (another controversial issue, I know I know), and it's entirely white, apart from the blue eyes (hence the reference to the zombies in Game of Thrones). The blue eyes offer a stark contrast in the fly itself, and the all-white fly is very contrasting to it's surroundings. The fly is app. 8 inches long!
The eyes are the new Pro Attitude Eyes from Pro Sportfisher (the silver version with blue marker over and then sealed with UV resin). The head is the also-new Pro Predator Cone (should be available in a very short time), also from Pro Sportfisher. Both great products and the fly really came together after Morten, the owner of Pro Sportfisher, handed me some samples of the new cones. They of course fit perfectly on the Pro Predator tubes, and add a little weight (if more is needed, add a second cone somewhere in the dressing), push water and protect the head of the fly from razor sharp teeth.
Have a great weekend!