The Big Fly Threshold

I’m a big fly guy. I love tying them, I love fishing them. We (fly fishing community) are constantly testing the boundary of big flies, and rewriting the definition. I remember years ago when I thought a 4″ Madonna was big fly. Now, I would consider it a small fly. But is there a point where big becomes too big? I think there is… Let me first address a disclaimer with big flies. I hear a lot of people say, and/or assume, that you need a big fly to catch a big fish. That is entirely untrue for anything I fish for. I fish big flies to avoid small fish. That, and the fact that I love tying and fishing big flies. But I know I can catch a big fish on small flies, its just not as fun to me. I always want to test how large a fly a fish will eat. Predator fish have always intrigued me. Even as a youngster, fishing for pike was one of my favorite things to do. Testing a fish’s predatory instincts with a large meal is somehow fun to me. It just is. Back to the original question…can big be too big? I think the biggest reason is action. As the size of a fly reaches a certain point, then you begin to sacrifice action. Depending on the pattern, that point could be 8″, or it could be 16″, or whatever that point of diminishing return is.  At some point you will begin to lose the enticing action of that specific pattern or fly that makes it successful. I’m not speaking of natural movement when the fly in the water, but your ability to manipulate the fly. Fly manipulation is incredibly important when streamer fishing. Is it worth sacrificing that? If a fish is looking for a bigger meal, I believe it has a threshold for what it considers “big”. Using trout as an example, will a 24″ trout (I would consider a brown trout of this size a “predator” fish) try to eat a 12″ trout in the right situation? Absolutely. If that 24″ trout was in the mood for a bigger meal, would it still eat a 8″ trout? I believe so. I would still consider an 8″ streamer a good size fly for trout. I can cast an 8″ fly easier, and manipulate it better, so in theory the 8″ fly would be the better big fly choice. Fishing the 12″ fly doesn’t necessarily mean I will catch more 24″ trout. Fishing the 8″ fly might, though.  I think all big fish have a “sweet spot” when it comes to meal size. With all that said, I will still continue to test the boundaries. Its just what interest me. I will throw a fly bigger than I think is the optimal size for a specific fish, just to see what will happen. In a world where bigger is always better, I don’t always think it is…although I will constantly try to find out.  And even if I conclude it can be too big, it doesn’t mean I will stop doing it.  Yeah, I’ve got problems.

8 Responses to “The Big Fly Threshold”

  1. Austin Orr says:

    I think you’re spot on with your observations – avoidance of small fish is probably the number one reason I scale flies up when in fresh water. Plus, why not push that boundary? I think that you’re right also about the sweet spot – physiologically, fish have to determine where the ratio is between big meal to tide them over vs size of prey item that they can actually eat without endangering themselves. We have all seen pictures of predator fish that have eaten a meal too large for them and have perished because of that, so it’s not always a hard and fast rule of course… but that’s what keeps us big fly guys going. Fun to tie, fun to catch fish on, fun to show off to the fishing buddies – big flies are where it’s at.

  2. Rich Strolis says:


    somehow, everytime I read your posts, I swear its like you have esp or something, or your a brother from another mother. We think the same, great post.

  3. Dan Podobed says:

    I love the sick, esoteric, interplanetary, deranged, drunk, high, delusional, damaged individuals within the large fly community. It’s beauty is like porn, it will only get bigger, more dangerous, more depraved.

  4. Mark says:

    I think you hit the nail of the head. This reminds me of years ago when I was one of those nasty bait guys. I was pretty hard core for stripers at Smith Mountain Lake in Virginia. Most of the time we were trolling Gizzard shad. We would net several dozen a day, some were small and went back. We didn’t want to catch 2 pound schoolies. Sometimes we would catch really really large shad in our nets, maybe up to a couple pounds. But what we really wanted was the hand sized shad. They not only caught the big fish, but would also catch the 10 pounders that were still fun to catch. These hand sized shad work so well that, at least on SML they are called “money makers”

  5. [...] you do not need a big fly to catch a big fish, Matt Grajewski pushes the boundaries of fly size, writing about the theory of design on his blog Fly [...]

  6. Simon Graham says:

    Big is bad,am glad you’ve eventually seen the light mate. Great article as well.

  7. Gary Cima says:

    While talking with Western fly fishing legend Del Canty of Colorado, we were discussing the big fly theory. Del summed it up like this, “You gotta throw him something he can make a living on”.

    I liked that and thought you guys would too!

  8. Christopher Andersen says:


    What kind of a rod do you use to throw a monster fly like that?

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