Anglers often wonder: What does brown trout eat? The answer depends on where they are, their size, and the season. Brown trout have yellow to olive flanks with black and red spots. They live from Scotland to Turkey and in 45 U.S. states.
Their diet changes based on the water they live in and what’s available to eat. In moving water, they eat mayflies, caddisflies, stoneflies, and midges. They also eat crustaceans like scuds, sowbugs, and crayfish.
Trout also eat fish eggs, worms after rain, and insects blown by the wind. As they grow, many brown trout become more aggressive. They chase minnows and young salmonids, and even smaller browns.
They can grow very big, up to 20 pounds. River adults usually grow 15–22 inches. They eat during the day and at night. They change how they hunt when there are lots of insects in the water.
So, what do brown trout eat? They eat a variety of things based on where they live and the season. This includes insects, crustaceans, small fish, eggs, and zooplankton in lakes. Knowing what they eat helps you understand their habits.
Brown trout basics: habitat, behavior, and why diet varies
Brown trout love cold water and steady flow. They like to stay near fast seams where food passes by. But they can also rest there.
They do well in streams with lots of oxygen below 70°F. They live in creeks, lakes, and even coastal waters. When food is plentiful, they focus on size, shape, and stage of the prey.
Cold, oxygen-rich waters and preferred cover
Brown trout like riffles, plunge pools, and shaded banks. These places have lots of fresh air. They hide behind boulders and logs to catch prey.
In hot weather or low water, they go deeper. They find deeper runs or turbulent heads of pools. This helps them balance oxygen and energy.
Stream, lake, and sea-run ecotypes influence feeding
There are different types of brown trout. River fish eat drifting nymphs and benthic insects. Lake fish start with zooplankton, then eat crayfish and baitfish as they grow.
Anadromous fish hunt inshore rips for marine bait. Then they go back to rivers to spawn. They often feed at dawn and dusk.
Opportunistic yet selective when prey is abundant
Brown trout are opportunistic until a hatch happens. Then they become very selective. They only eat the right stage of insects.
In low light, wind, and rising flows, they become bolder. They strike from cover while saving energy between strikes.
Aquatic invertebrates: the everyday menu in rivers and streams
In moving water, brown trout eat small prey that drifts by. These trout insects live in riffles and seams. Anglers use patterns like Pheasant Tail and Hare’s Ear to match this menu.
Mayflies, caddisflies, stoneflies, and midges
A mayfly hatch can change everything in streams. Fish eat emergers and spinners, then nymphs when it’s over. Caddisflies bring adults that trout chase, while stoneflies stay near the bottom.
Midges are small but important in tough times. Trout eat tiny pupae and emergers in soft water. Matching size and stage is key during hatches.
Crustaceans: scuds, sowbugs, and crayfish
Spring creeks and tailwaters have scuds, sowbugs, and crayfish. These offer steady food for trout. Crayfish are big and full of energy, so trout look for them under rocks.
Weed beds are home to these crustaceans. They’re as important as insects when the water is clear.
How hatches drive seasonal feeding
Season and temperature control when trout eat. In cold months, they eat stonefly nymphs and slow mayfly nymphs. As it warms, mayflies and caddisflies bring them to the surface.
During peak times, trout are very picky. They move from bottom to top with the food. So, timing and presentation are key when there’s a lot of food.
| Food Source | Key Stage Eaten | Best Water Type | Seasonal Peak | Angler Match |
|---|---|---|---|---|
| Mayflies | Nymphs, emergers, spinners | Riffles, tailouts | Spring–early summer; fall | Pheasant Tail, Parachute Adams |
| Caddisflies | Larvae, pupae, adults | Broken seams, bankside runs | Late spring–summer | Hare’s Ear, Elk Hair Caddis |
| Stoneflies | Stonefly nymphs, adults | Fast pocket water | Late winter–spring; midsummer (local) | Prince Nymph, Stimulator |
| Midges | Larvae, pupae, emergers | Tailwaters, slick glides | Year-round, strongest in winter | Midge pupa, Griffith’s Gnat |
| Scuds & Sowbugs | All stages | Spring creeks, weed beds | Year-round, stable flows | Scud, Soft Hackle Sowbug |
| Crayfish | Juveniles, adults | Gravel bars, rocky banks | Late spring–fall | Crayfish pattern, Woolly Bugger |
From dawn to dusk, hatches control trout behavior. Whether it’s a big mayfly hatch or a quiet day on stonefly nymphs, understanding the drift is key.
Piscivory: when brown trout hunt fish
As brown trout grow, they start to hunt fish. This change means they catch bigger prey. This is common in rivers, reservoirs, and estuaries.
Why large browns shift to baitfish
Big trout save energy by eating baitfish instead of insects. Eating a sculpin or minnow is like getting dozens of insects. This also helps young fish by reducing competition.
Common prey, including their own species
Minnows, sculpin, and young salmonids are favorite foods. In tight spaces, they even eat their own kind. In lakes, they chase schools of smelt or shiners near points.
Predatory behavior in low light and under cover
Brown trout ambush their prey. They hide behind boulders or undercut banks. Then, they quickly attack.
Anglers use streamer flies to catch them. Woolly Bugger and Muddler Minnow are good choices. In murky water, use crankbaits and spinners for extra flash.
What does brown trout eat
Brown trout eat a lot because they adapt quickly. In moving water, they mostly eat aquatic invertebrates like mayflies and caddisflies. They also eat crustaceans like scuds and crayfish when currents bring them by.
As they grow, they start eating fish. They eat dace, sculpins, and even smaller browns. In estuaries, they go after schools of baitfish.
They are opportunistic eaters. They eat fish eggs when redds are active. After storms, they eat earthworms. On windy days, they eat beetles and ants.
Young fish start small and get bigger. Fry eat tiny larvae. In calm water, they eat zooplankton and daphnia. As they grow, they eat crayfish and minnows.
Below is a quick glance that ties habitats to choices and keeps a clean trout diet summary for anglers and biologists alike.
| Habitat | Core Foods | Notable Add-ons | Feeding Notes |
|---|---|---|---|
| Rivers & Streams | Mayflies, caddisflies, stoneflies, midges | Scuds, sowbugs, crayfish; small fish | Hatch-driven; low light boosts ambush |
| Stilwater | Zooplankton and daphnia (small fish) | Crayfish, minnows as size increases | Edges and weed lines concentrate prey |
| Estuary & Coast | Baitfish schools | Shrimp and small crabs | Tide cycles set feeding windows |
| Any System | Terrestrial insects | Trout eggs worms zooplankton when available | Rain, wind, and spawning events drive spikes |
The brown trout food list changes with water type, season, and size. Watch what trout eat in your water. You’ll see what they eat, from nymphs in riffles to minnows in the dark.
Stilwater diets: lakes, reservoirs, and ponds
Calm water changes how browns feed. The lacustrine morph, S. trutta morpha lacustris, tracks prey bands along drop-offs and weedlines. Thermoclines can stack forage into neat layers, shaping lanes that reward patient cruisers and those tuned to energetics.
Zooplankton and daphnia for smaller trout
Juveniles start pelagic, picking at clouds of daphnia zooplankton trout where light and temperature meet. This early phase anchors the lake trout diet (Salmo trutta) before a shift to shoreline macroinvertebrates. When stratification tightens, young fish shadow microfronts where tiny prey bunch up.
Crayfish and minnows for larger fish
As bodies lengthen, the menu scales up to crayfish minnows forage along rocks, docks, and cattail edges. In many impoundments, reservoir brown trout food centers on soft-rayed baitfish like alewife or juvenile perch, with crayfish adding crunch and calories. Bigger bites mean fewer chases and faster growth.
Energy trade-offs in calm water vs. current
With no river push to fight, adfluvial browns budget more power to growth and short bursts of speed. This helps explain record sizes, from Europe’s alpine lakes to New Zealand’s Ohau Canal giant in 2020. The same energetics model guides their cruising, pinning prey, and suspending over the thermocline.
| Forage Type | Primary Zone | Best Conditions | Caloric Return | Angler Cue |
|---|---|---|---|---|
| Daphnia and mixed zooplankton | Pelagic edges near thermocline | Stable stratification, low wind | Low per item, high density | Fine-mesh slicks, dim midday light |
| Scuds and aquatic nymphs | Littoral weeds and marl flats | Clear water, moderate sun | Moderate | Weedbed swirls, shore prowling |
| Crayfish | Rock piles, riprap, stump fields | Warm evenings, low chop | High | Short, explosive ambushes tight to cover |
| Minnows and soft-rayed baitfish | Bays, inlets, and drop-offs | Dawn, dusk, and overcast | Very high | Surface dimples, bait balls on sonar |
| Spillway and inflow drift | Reservoir mouths and current seams | After rain or managed releases | High, low effort | Foam lines and suspended cruisers |
Across lakes and reservoirs, reservoir brown trout food shifts with season and structure. The lake trout diet (Salmo trutta) scales from daphnia zooplankton trout to crayfish minnows forage as fish grow, while energetics principles keep the math in their favor.
Seasonal and lifecycle shifts in feeding
Brown trout change their diet as they grow and with the seasons. Their diet changes with water temperature, flow, and insect hatches. This shapes their menu from spring to winter.
Fry and fingerling first foods: chironomids and baetid nymphs
Fry start eating fast right after they hatch. They eat tiny chironomid larvae and baetid nymphs near the water’s edge. These small bites are full of energy, which is important when they face a lot of danger and competition.
As the water warms up, trout start eating more. They add micro-crustaceans and midge pupae to their diet. Eating well early on helps them grow fast in their first summer.
Juvenile to adult transitions reduce competition
As trout get bigger, their diet changes. Young trout eat caddis, mayflies, and stoneflies. Bigger fish start eating sculpins and dace, along with larger nymphs. This helps them avoid fighting over food in tight spaces.
Adult trout become more fish-eaters and pick the best spots to eat. They save energy by waiting for prey to come to them. The quality of their habitat and how much oxygen is in the water affects how fast they make this change.
Fall spawning season and egg-eating opportunities
In the fall, trout make nests in gravel and their diet changes again. Trout and other fish lay eggs that drift in the water. Trout eat these eggs, which are a quick and high-energy food source.
To learn more about the trout lifecycle, check out this overview. Knowing about each stage helps you match your fishing tactics to the trout’s diet at different times.
Terrestrial food sources and opportunistic snacks
Brown trout don’t just eat bugs. They also eat food that falls into the water. This includes bugs, worms, and even small animals. They eat these things because of the weather, water flow, and where they hide.
Worms after rains and wind-blown insects
After it rains, worms come out. They fall into the water, where trout wait. On windy days, bugs like ants and beetles fall into the water too. Trout love to eat these bugs in the summer.
In meadow creeks, a little wind can make trout eat all day. In rivers, wind pushes bugs into the water. Trout then swim up to eat them.
Occasional amphibians, small mammals, and birds
Big trout eat whatever they can. They eat mice, frogs, and small birds near the water. This is because the water is calm and there are places to hide.
When the water rises, salamanders and toads move into the current. This makes a big feast for trout.
Why browns feed day and night
Trout eat bugs in the daytime. But at night, they hunt for meat. They do this when it’s dark and the water is a bit murky.
Trout can switch from eating bugs to hunting at night. This is true in many kinds of water.
| Trigger | Primary Food Source | Best Holding Water | Typical Feeding Window | Tactical Note |
|---|---|---|---|---|
| Post-rain surge | Worms trout rain, dislodged nymphs | Inside bends, soft seams, back eddies | First 2–6 hours of dropping flows | Dead-drift a worm pattern tight to the seam line |
| Wind events | Terrestrial insects trout like ants, beetles, hoppers | Undercut banks, grassy margins, overhanging brush | Midday to late afternoon in summer | Short drifts under cover; pause on the hang |
| Warm nights | Mice frogs trout, small birds near water | Cutbanks, logjams, weed beds, side channels | Dusk through early morning—nocturnal trout feeding peak | Slow swing or wake a surface pattern along structure |
| Stained water | Mixed forage—signals an opportunistic trout diet | Edges of color change, tributary mouths | All day with crepuscular bumps | Use bold profiles and moderate retrieves |
Geography matters: U.S., New Zealand, and Australia feeding patterns
Brown trout eat what each water gives them. Climate, flow, and forage shape their diet. In the U.S., they eat what rivers offer. But in distant islands, they grow fast and hunt hard.
Across Oceania, early stockings help big fish thrive today.
United States rivers, tailwaters, and spring creeks
Cold tailraces and limestone creeks feed trout well. They eat midges, sowbugs, and scuds. Mayflies and caddis hatches also come often.
Freestones add stoneflies and terrestrials after storms. As browns grow, they eat minnows and crayfish. This fuels big fish.
The U.S. diet is small bugs for numbers and baitfish for size.
New Zealand’s big-brown environments and baitfish focus
Canals, rivers, and lakes in New Zealand are full of food. This helps trout grow fast and big. Canal edges and inlets have smelt and bullies.
Management paired introductions with prey fish in places like Lake Taupō. This is explained in this feature on the lure of trout. In open rivers, mayflies and stoneflies matter, but baitfish and yabbies are key for trophy browns.
Australia and Tasmania’s cool streams and sea-run influences
Cool creeks in New South Wales, Victoria, South Australia, and Western Australia feed trout well. Estuaries and coastal streams add prawns, crabs, and whitebait. This expands trout distribution along shorelines.
Tasmania sea-run trout chase anchovies and sprats in the sea. Then, they return to fresh water for scuds and mayflies. This marine buffet pushes fast growth. Inland impoundments offer yabbies and galaxias to keep big fish on the hunt.
| Region | Primary Forage | Key Waters | Notable Pattern |
|---|---|---|---|
| United States | Tailwater trout food (midges, sowbugs), spring creek scuds, crayfish, baitfish | Tailraces, limestone creeks, freestones, reservoirs | Bug-rich flows feed numbers; baitfish shift grows trophies |
| New Zealand | New Zealand brown trout baitfish (smelt, bullies), large stoneflies, koura | Lake Taupō, Tongariro River, South Island canals | Low density plus rich forage speeds growth |
| Australia & Tasmania | Estuarine invertebrates, whitebait, galaxias, mayflies | Coastal streams, estuaries, Tasmanian rivers | Tasmania sea-run trout exploit marine baitfish |
Habitat features that concentrate food
Brown trout like to be where food and cover meet. They hide under undercut banks, where roots and sod make quiet spots. These places are perfect for them to wait for food to come by.
Movement lines are important too. Current seams are great because insects drift by slowly. Browns can easily catch them here. Eddies below boulders and logs also gather food, making it a feast for trout all day.
Riffle-to-run transitions are full of oxygen and food. Mayflies and stoneflies fall from cobble here. Weedbeds in spring creeks hide scuds and sowbugs, and soft edges and backwaters are full of worms and insects after rain.
Depth changes help trout too. Deep pools are safe in winter, and fast water is cool in summer. Moving between shade, depth, and flow is key for finding food.
Even in lakes, habitat shapes patterns. Littoral rock, submerged timber, and inflow deltas attract crayfish and baitfish. Thermoclines have zooplankton and small minnows, guiding trout to them at dawn and dusk.
| Microhabitat | Why It Collects Food | Primary Forage | Best Conditions | Angler Cue |
|---|---|---|---|---|
| Undercut banks | Shade, slower boundary layer, overhead cover | Terrestrials, small baitfish, sculpins | Bright days, stable flows | Probe tight to the edge; short, accurate casts |
| Current seams | Converging flows deliver steady drift | Mayfly and caddis nymphs, midges | Moderate to high flow | Fish the line where fast meets slow |
| Eddies and boulder pockets | Recirculation traps insects and baitfish | Stonefly nymphs, drowned ants and beetles | After flow spikes or wind | Target foam lines and soft cushions |
| Riffle-to-run transitions | High oxygen and constant nymph export | Mayflies, stoneflies, sowbugs | Overcast or low light | Dead-drift nymphs, then lift at the drop |
| Weedbeds (spring creeks) | Complex habitat for invertebrates | Scuds, sowbugs, snails | Clear, steady spring flows | Slow presentations along edges |
| Soft banks and backwaters | Low velocity collects debris and worms | Worms, terrestrials, midges | After rain or wind events | Drift natural patterns near mats and foam |
| Deep pools with inflow | Thermal refuge and cover | Baitfish, leeches | Heat waves and winter lows | Swing streamers along the drop-off |
| Littoral rock and timber (lakes) | Ambush cover and forage corridors | Crayfish, minnows | Dawn, dusk, low light | Work parallel to shoreline structure |
| Thermocline edges (lakes) | Comfort band concentrates prey | Zooplankton, young-of-year baitfish | Mid-summer stratification | Count down to the band; steady retrieves |
| Inflow deltas (lakes/reservoirs) | Nutrient pulses draw schools | Smelt, shiners, insect drift | After rain or snowmelt | Fan casts across the fan-shaped drop |
Undercut banks, current seams, and oxygen refuge spots are key. These places are where trout feed, guided by structure and forage. They move with water and light, making these spots reliable for finding them.
Angler insights: matching the menu for better success
Start by looking at the water in front of you. Then, match what brown trout eat there. In moving water, use Pheasant Tail, Hare’s Ear, Prince Nymph, Elk Hair Caddis, and Parachute Adams.
When stoneflies are around, use Girdle Bugs or a bulky stonefly nymph. In tailwaters, midges are active all year. Scud or sowbug patterns work well in spring creeks and below dams. Keep your drift straight through seams and soft edges.
When trout become predators, switch to streamer fishing. Use Woolly Buggers and Muddler Minnows at dawn, dusk, and night. Swing or strip along banks, wood piles, and boulders to wake up big trout.
In calm water, start small with chironomids and leeches. Then, move to crayfish and baitfish imitations as water warms and trout grow.
Fall is the time for egg patterns for trout. Use them where it’s legal and eggs are present. Present them with care, adjust weight for depth, and avoid active redds. Low light is best for catching large browns, so plan your fishing around first and last light.
Choose the right gear for the job. A 3- to 6-weight rod with a floating line works for most flies and nymphs. Use a heavier rod for windy lakes or bigger streamers. Keep leaders strong enough to turn flies over but light enough for clear water. By reading the menu and structure, your chances of catching trout will improve quickly.
