Fly Fishing Lessons: Trout Eyesight 101 | How Do Trout See?

Short answer – pretty differently than we do.

Trout have eyes on the sides of their head for a reason. | Photo by Mark Pickrel

Trout face upstream, so they can only see you if you’re upstream of them – right? Logical assumption, but not right. That might be the case if it were a human facing upstream, but trout have eyes that are designed to work a little differently. 

A Trout’s Field of Vision

Trout’s eyes are located on the sides of their heads, which gives them a pretty wide field of vision. Their eyes are designed to take in movement happening on each side of them, leaving narrow blind spots directly in front of and behind the body. So casting into a pool parallel to you? Sometimes necessary, but not advisable. 

Above The Surface

It would be nice to think that trout can’t see you walking on the bank from their vantage point underwater. Hate to burst your bubble, but they can. Trout have a cone-shaped window of vision through the water’s surface – within the cone, trout can see insects, birds, and, yes, you. 

Color Vision 

Trout can see color, but light conditions, water clarity, and depth in the water column all have a significant effect on the clarity with which they can see it. Keep it in mind when you’re choosing a fly –  on a bright day with clear water and fish feeding near the surface, the color of your fly will matter much more than in low-light conditions with stained water and fish holding deep. 

Low Light Vision

Trout’s eyes are adapted to low light, so even if you’re fishing early morning or late evening, they’ll still be able to see you and your fly fairly well. That said, the less light trout have to work with, the more they rely on feeling their surroundings – trout have a system of sensory organs that help them feel vibrations underwater, and it works pretty damn well. 

How to Present a Fly They’ll See

Understanding how a trout sees makes it a whole lot easier to offer a fly that it’s willing to take –  while it’s important to match the size, color, and shape of the insects trout are feeding on, it’s even more important to put it in a place where it will be seen. Consider the conditions – if the water is clear, you can expect a trout to see your fly from a decent distance, but if it’s stained, you’ll likely have to run it right by the trout’s nose. 

Test It Out

Cast from different angles, fish in low light and in daylight, clear water and stained water – with time, you’ll develop an idea of what a trout might be seeing based on the conditions. You’ll never be able to see the way a trout can, but you can train yourself to understand its perspective.