Biology of Fly Fishing - Part 1

8 CommentsFriday, 30 November 2018  |  Paul G

Biology of Fly Fishing: Part 1 of "A Biohacker's Guide"

So much conventional wisdom and information in fly fishing ignores basic knowledge that has been around for decades in the science of animal behavior. 

Surprisingly, it can be a huge short-cut to discover how visual predators (including trout) recognize "food". This can save a lot of the leg work (and space in your brain!) that's involved with learning fly fishing flies and tactics fact-by-fact. You can now get this full strategy via our Amazon Affiliate links (for which we earn commissions that subsidise our site and YouTube Channel) for both Digital and Physical versions of the book "How to Fool Fish with Simple Flies":

Kindle version:

8" x 10" Full Colour Print Book:

Here's the first episode that lays out the foundations:

Catch Up on Other Episodes in this Series

Click for Episode 2

Click for Episode 3

Click for Episode 4 (Finale)

Fast Track Biology for Fly Fishing

The entire basis of fly fishing is to fool a fish into accepting your (entirely artificial) fly pattern as if it were genuine prey. Because of this, the whole activity boils down to "hotwiring" the systems that fish normally use to recognize what is worth eating (and how to tell that apart from general crap drifting past!). So, while you don't have to throw out what you know already, you can help to make your knowledge more effective by looking at it in the light of some extra biological info...

To Get The Full Picture - Check out our Special Biohacker's Email Tutorial Series and Subscribe using the Form Below:






Eberhard Scheibe
Saturday, 1 December 2018  |  12:12

Entertainment, Learning and working on some "things" I haven't thought on before. Some details I have noticed before are coming out of my old brain. I'm a retired student. Thanks fo your stuff.

Paul G
Saturday, 1 December 2018  |  12:34

Thank you too Eberhard - I am sure that you're being too modest :)


Paul Procter
Saturday, 1 December 2018  |  12:53 a seasoned fly fisher, in my haste, sometimes I forgot the simplest of lessons which are vitally important, these are eloquently reinforced here by Paul.

Paul G
Saturday, 1 December 2018  |  13:09

Very many thanks Paul - it means a lot to have someone at your outstanding level make those comments.


David Glater
Sunday, 2 December 2018  |  5:07

Looking forward to reading these comments.

Paul Gaskell
Sunday, 2 December 2018  |  20:02

Thanks David - me too!

I think that there'll be lots to talk about on the Biohackers Episode 2 broadcast - because there's so many case study (video and photo) examples of really fun fishing experiences.


Andrew Griffiths
Thursday, 6 December 2018  |  18:12

Hi Paul,
Really enjoyed this, but just a thought:
Re: the bushy fly on the riffle, and the skinny fly on flat - do you think there could be an element of angler biology in there, to accompany the fish biology hack? I am thinking bite detection - easier to detect a take on broken water with a big, bushy fly than a skinny one. I wonder if that may skew one's impressions to some degree? Just a thought.

Paul Gaskell
Thursday, 6 December 2018  |  18:51

Hi Andrew, I'm sure there can be an element of that - especially where the naturals are in that 'medium' size range around 14s and 12s hook sizes. I'd also say there's probably an asymmetry (as long as the cast is accurately covering fish in the broken water). What I mean is, a fly that's a bit too small in rough water is probably a bit more acceptable than a fly that's too big/overdressed in flat water. BUT, if you don't know how close to the fish your small fly is (I.e. if you're having trouble seeing fish taking your fly in rough water, there's little chance you're seeing them take naturals) then why not treat yourself to the added bonus of making your fly both more noticeable to the fish (and you) AND able to "pull" fish from further away (due to better apparent calorific payoff)?

Finally, there is a purely practical consideration that you'll spend more time applying floatant to keep a super sparse dry fly afloat in riffles than with a bushier pattern - possibly including some dry fly yarn/aero-wing or similar. That's an opportunity cost when you could be showing that fly to fish instead of squeezing it out on your drying patch.


PS, broadcasting part 3 live in just over an hour from now on the Tenkara in Focus Facebook page.