Dry FliesCow Killer Ant

The Cow Killer Ant is a terrestrial pattern used to imitate a large ant species. It is highly effective due to its vivid red color and realistic shape, which can trigger aggressive responses from fish, especially during terrestrial seasons.

Season
Summer
Difficulty
Intermediate
Target Species
Trout, Bass
Cow Killer Ant - Image source: Rainy's Flies
Image source: Rainy's Flies

Overview

Constructed from two foam cylinders (black and red), rubber legs, and sometimes a dubbed thorax, this fly imitates a terrestrial ant with high floatation and visibility. The segmented foam bodies are super durable for aggressive strikes.

Pattern Characteristics

Intermediate Difficulty
Trout, Bass
Stillwater
Moving Water
Summer
Imitates: Ants

Materials

Hook: Tiemco 100, size #12–#16
Thread: Red UTC 70 denier
Body: Red dubbing
Wing: White poly yarn
Legs: Black rubber legs
Shell: Solarez Bone Dry UV resin

Fishing Tips

Season

The Cow Killer Ant is most effective in the summer when ants are active and often fall into the water.

Presentation

This is a dry fly, so use standard dry fly presentations such as upstream and across. It can also be effective when drifted along the bank or under overhanging trees where ants may fall into the water.

When to Use

Use the Cow Killer Ant during the warmer months, especially in the height of summer when terrestrial insects like ants are active and plentiful.

Water Type

This fly is effective in both stillwater and moving water. It can be especially effective in small streams with overhanging foliage.

Rigging Suggestions

Fish this fly on a standard dry fly leader, with a 5X or 6X tippet depending on the size of the fly and clarity of the water.

Visibility & Floatation

This fly is relatively easy to see due to its size and the white poly yarn wing. It floats well due to the dry dubbing body and the UV resin shell, which adds durability and shine, making it more visible to fish.