I built a mini aquarium out of ultra-thin plastic (0.030mm) so I could more easily see what trout see. Something I – and most of you – have wondered is how visible a real or fake fly’s wings are to the trout. For this post, lets focus on Mayfly duns. This first experiment was done with a female hendrickson dun.
This first pic was taken 3-feet theoretically downstream, at a depth of 3-feet, which put me at a 45-degree angle to the bug. Feel free to do the trig if you’d like to figure out exactly how far my camera lens was away from the bug. See that small indentation in the center of the water? Thats our dinner, should we choose to accept it.
- At this point in the game, size/shape/color does not matter.
- The somewhat popular notion that the wing is the first thing a trout sees is bunk – at least at this distance/depth/angle. Don’t forget this is stillwater. Moving water would have even more scattered reflections and air bubbles, etc., making a wing even harder to see.
This next photo was taken at 2-feet downstream from our bug, at a 2-foot depth, and again, a 45-degree angle.
- At this point in the game, color still doesn’t matter.
- Size seems like it should, and shape might just be starting to.
Here we are at our next photo. We’re now 1-foot downstream and 1-foot deep, again, at a 45-degree angle. This is that spot where the angler usually sees the fish swim up to “inspect” the artificial fly pattern. Now we’ve got all sorts of reflections and light play going on. Its also a lot easier to see the dent in the meniscus.
- I was really surprised I still didn’t see a wing at this point. I knew refraction was going to throw a few curve balls, but this really surprised me.
- Shape and color still don’t matter nearly as much as size and presentation (how high your fly is floating in the film)
Time to get up close and personal. We’re about 3-inches downstream and about 3-inches deep, still at about a 45-degree angle. The ONLY reason we can see the wing here is because our bug floated towards the near-side of the tank.
- Even at this close, in still water, and with the fly turned completely sideways, the wing doesn’t really matter.
- Size, shape, and presentation matter a whole lot.
- Color seems like it matters, but if I backlit this bug to simulate the sky, I don’t know if it really would to any major extent. Color should matter more on cloudy days.
Here is our bug from directly underneath. Keep in mind, if the trout’s eye is this close, that means the fly has already drifted past its mouth. Also keep in mind that if a trout is rising to our bug, at this point in the rise, the fly is in the trout’s blind spot and the trout can’t see it anyway.
- Color finally seems to matter – if the fly isn’t in the trout’s blind spot.
- We can finally see a wing – if the fly isn’t in the trout’s blind spot.
- The only time color/wings matter is for those fish that come up and have the time to drift downstream with the fly. We’ve all seen it. Though from my experience, most fish are getting ready to unleash the suck somewhere at about the photo above. In my opinion, the only time you should worry about color is if you’re off on your size, shape, and presentation. If you have those right, the fish is eating your fly before it gets this close.
My opinion on if you get a refusal at this point, it is because the fly went into the trout’s blind spot and the fish, having a brain the size of a pea, probably thought the fly just disappeared into outer space or something. It didn’t actually refuse. It simply said, the food is gone, no sense sticking around the surface where all the predators can see me.
Still lots of questions to ask and experiments to do…