Trout Behavior: Understanding Your Quarry

Understanding how trout think, feed, and react to their environment will make you a more successful angler.

Trout Senses

Vision

What trout see:

• Can see above and below water
• Wide field of view (nearly 360°)
• Can detect movement easily
• Color vision (similar to humans)
• Better in low light than humans

Above water view:

• Circular “window” through surface
• Outside window: reflection of bottom
• Objects in window appear closer than they are
• Refraction makes your position hard to judge

Implications for anglers:

• Stay low when approaching
• Wear drab colors (bright colors spook fish)
• Move slowly
• Your shadow is your enemy
• Fish can see you more than you think

Lateral Line

What it is:

• Series of pores along fish’s sides
• Detects vibration and pressure changes
• Works in murky water and darkness
• Highly sensitive

Implications:

• Wading carefully is critical
• Don’t crash around in the water
• Move deliberately
• Fish sense you before they see you
• Especially important in stillwater

Smell

Trout have excellent scent:

• Can detect predators
• Find food by scent
• Detect unusual odors (sunscreen, bug spray)
• Scent travels in water

Implications:

• Avoid scented lotions before fishing
• Don’t handle flies with scented hands
• Some anglers use scented attractants
• Wash hands before fishing

Hearing

Trout hear well:

• Internal ear detects sound
• Vibration through water carries well
• Can hear you walking on the bank
• Splashy casts spook fish

Implications:

• Walk softly on the bank
• Don’t wade noisily
• Gentle presentations
• Quiet approach = more fish

Feeding Behavior

Selective Feeding

What it means:

• Trout focus on one insect stage
• Refuse other offerings
• Common during heavy hatches
• Can be extremely frustrating

Why it happens:

• Energy efficiency (one food source abundant)
• Pattern recognition
• Avoid confusing insects
• Safe feeding strategy

How to handle it:

• Match the hatch precisely
• Observe what fish are eating
• Catch an insect if you can
• Size is most important
• Profile second, color third

Opportunistic Feeding

What it means:

• Trout eat whatever drifts by
• Not focused on one insect
• Most common situation
• More forgiving for anglers

When it happens:

• No major hatch occurring
• Early season
• Off-color water
• Less educated fish

Strategy:

• Attractor patterns work
• Standard patterns fine
• Less need for exact matching
• Presentation more critical

Feeding Stations

What they are:

• Prime feeding spots
• Fish return repeatedly
• Consistent food delivery
• Energy-efficient position

Types:

• Current seams: Food funnel
• Behind rocks: Current break + food
• Drop-offs: Depth change + food
• Pool heads: First good feeding after riffle

How to fish:

• Observe where rises occur
• Fish feeding lanes methodically
• Don’t line the fish
• Cover the water thoroughly

Trout Hierarchies

Size-Based Hierarchy

Larger fish:

• Get prime feeding lies
• Dominate best spots
• Push smaller fish aside
• More challenging to catch

Smaller fish:

• Marginal holding areas
• Feed when larger fish aren’t
• More numerous
• Easier to catch

Implications:

• Largest fish in best spots
• Need accurate casts to big fish
• Smaller fish easier to approach
• Catch smaller fish first if targeting a trophy

Territorial Behavior

Trout defend space:

• Feeding stations are territories
• Chase away intruders
• Establish dominance hierarchies
• Especially true in productive water

Daily Activity Patterns

Dawn

Fish behavior:

• Active feeding
• Moving into shallow water
• Mayfly spinners often
• Cooler water temperatures
• Lower light levels

Fishing strategy:

• Early morning hatches (tricos)
• Streamers for active fish
• Dry fly fishing to rising fish
• Arrive before first light

Mid-Morning to Mid-Day

Fish behavior:

• Less surface activity
• Move to deeper water
• Nymph feeding primary
• Shade becomes important
• Especially true in bright sun

Fishing strategy:

• Nymphing deeper water
• Terrestrials during summer
• Indicator fishing
• Fish structure thoroughly

Late Afternoon to Dusk

Fish behavior:

• Increasing activity
• Move to feeding lies
• Caddis hatches begin
• Mayfly spinner falls
• Best dry fly fishing

Fishing strategy:

• Prime dry fly time
• Stay until dark
• Spinner falls at dusk
• Caddis egg-laying activity

Night

Fish behavior:

• Large fish move shallow
• Feed aggressively
• Less cautious
• Risk-taking behavior

Fishing strategy:

• Large streamers
• Mouse patterns
• Dangerous wading
• Requires experience

Seasonal Behavior

Spring

Pre-spawn:

• Aggressive feeding
• Building energy for spawning
• Good fishing opportunity
• Please avoid redds

Spawn:

• Fish on redds (spawning beds)
• Don’t fish to spawners
• Let them reproduce
• Look for non-spawning fish

Post-spawn:

• Recovering but feeding
• Good fishing returns
• Hungry fish

Summer

High water temps:

• Fish seek cooler water
• Early/late fishing
• Deep water holding
• Spring creeks, tailwaters
• Fish stress (handle carefully)

Low water:

• Clear, spooky fish
• Light tippets required
• Delicate presentations
• Terrestrial insects important

Fall

Pre-winter feeding:

• Aggressive feeding
• Preparing for winter
• Streamer fishing excellent
• Blue-winged olives

Second spawn:

• Some species spawn again
• Respect redds
• Fish non-spawners

Winter

Cold water:

• Slowed metabolism
• Less active
• Conserve energy
• Feed less frequently

Fishing:

• Mid-day warmest
• Nymphing primarily
• Small flies
• Slower presentations

How Trout Hook

Rise Forms Tell the Story

Splashy rise:

• Taking duns on surface
• Or chasing emerging caddis
• Size 12-18 insects typically

Subtle dimple:

• Sipping spinners
• Or small emergers
• Size 20-26 insects

Porpoising:

• Feeding just below surface
• Emergers or nymphs
• Not taking duns

Jumping:

• Not necessarily feeding
• May be escaping
• Or chasing hatching insects

Tailing:

• Feeding on bottom
• Nymphs
• In very shallow water

Hook Sets

Dry fly:

• Gentle lift, not strip-strike
• Wait for fish to turn
• Quick but smooth

Nymphing:

• Set on any indicator movement
• Quick downstream lift
• More aggressive than dry fly

Streamer:

• Strip-strike effective
• Fish often hook themselves
• Keep tension

Spooked Fish Behavior

Signs fish are spooked:

• Refuse to feed
• Dart for cover
• Stop rising
• Flash (turn sideways in fright)

Recovery time:

• 15-30 minutes typical
• Some fish never recover
• Others return quickly
• Depends on pressure

Understanding Makes You Better

When you understand trout behavior:

• You know where to look
• You understand what they’re eating
• You can predict their movements
• You become more successful
• You appreciate the fish more

The Learning Never Ends

Every trip teaches you something:

• Watch how fish feed
• Note where they hold
• Observe their reactions
• Remember successful approaches
• Learn from mistakes

The best fly fishers are also the best students of trout behavior. Never stop observing, never stop learning.

The more you understand about trout, the more you’ll catch - and the more you’ll appreciate every encounter with these remarkable fish.