What Size Fly Is Best for Trout?

When it comes to fly fishing for trout, one of the most important factors to consider is the size of the fly you are using. Trout can be very selective when it comes to what they choose to eat, so choosing the right size fly can make all the difference in your success on the water.

What Size Fly is Best for Trout?

The size of the fly you should use for trout depends on a variety of factors. These include the time of year, water conditions, and the specific species of trout you are Targeting.

Time of Year

During different times of the year, trout will be feeding on different insects. For example, in the spring and early summer, there may be a lot of hatches of small flies like midges and mayflies. During this time, smaller flies in sizes 16-24 may work best.

In late summer and fall months, larger insects like grasshoppers and stoneflies become more prevalent. This means that larger flies in sizes 4-10 may be more effective.

Water Conditions

Water conditions also play a role in determining what size fly is best for trout. In clear water with low flow rates, smaller flies will be more effective as they are less likely to spook the fish. In murky or fast-flowing water, larger flies may be necessary to grab a fish’s attention.

Species of Trout

Different species of trout also have varying preferences when it comes to fly size. Generally speaking, brown trout tend to prefer larger flies while rainbow and brook trout will go after smaller ones.

  • Brown Trout – Size 4-10
  • Rainbow Trout – Size 16-20
  • Brook Trout – Size 16-22

Pro Tip: When in doubt, it’s always a good idea to start with a smaller fly and work your way up in size until you find what the fish are biting on.

The Bottom Line

In conclusion, the size of the fly you should use for trout depends on a variety of factors including time of year, water conditions, and species of trout. By taking these factors into consideration and experimenting with different sizes, you can increase your chances of success on the water. Happy fishing!

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Emma Gibson