Trout do not typically sift through bottom sediment while feeding. However, they do predominantly feed near or just off the bottom. Trout prefer to feed in 2-3 feet of water where they intercept food as it drifts by.
When trout fishing, it is quite easy to develop the opinion that trout spend a lot of time eating insects from the surface. After all, the rings of a rising trout are often the most visible to an angler.
The reality is quite different, and trout spend relatively little time feeding from the surface. In most river fisheries, the trout we see feeding from the surface make up a tiny portion of all the trout in the water. It has been estimated that trout typically feed on the surface around 10% of the time. With an additional 10% of prey taken just below the surface.
This means trout get approximately 75% percent of their diet within a couple of feet from the bottom. The bottom is where most of their food lives and grows. While trout prefer to eat food which is floating off the bottom, trout at times do dig into the sediment and suck up exposed insects or mollusks.
While trout spend the majority of their time feeding and holding near the bottom. They always watch their surroundings and will rise higher in the water column to grab a tempting enough morsel. They are not true bottom feeders like catfish or carp that spend their time digging through the sediment.
Do trout feed on the bottom?
Trout typically feed close to, or just off the bottom. Approximately 75% of a trout diet is taken near or on the bottom.
At times trout do suck caddis larvae, mayfly nymph, and snails right off the bottom. Just like a bonefish, trout will bury their nose into the sediment to dislodge a meal. I am also certain they will grab any worm that peeks too far out of their holes.
In rivers, trout eagerly eat any crayfish they catch out in the open. Probably more so at night than during the day. I once watched, several brown trout in an estuary patrol a shallow flat consuming small mud crabs right off the bottom. I know one lake where freshwater mussels make up a large portion of their diet.
So trout also feed upon juvenile freshwater mussels, clams, and other mollusks. Trout are not fussy eaters. In some waterways, trout and mollusks share a symbiotic relationship. The trout eat the mussel spawn, which then attaches to the trout gills and hitches a ride to other parts of the lake or river.
Below is an excellent video that shows a rainbow trout digging into the sandy bottom in search of a meal.
How deep do trout feed in lakes?
The depth at which trout feed in lakes varies based on several factors, including the species of trout, water temperature, available food sources, and lake conditions. However, in general, trout are known to be versatile feeders and will typically be found where their preferred prey is.
And, that prey typically occur within the area of the lakes that receives sunlight. Even in clear low-nutrient lakes (oligotrophic) light rarely penetrates deeper than 20 to 30 meters (approximately 66 to 98 feet). Within this zone is where most feeding will take place, although trout are normally found in the upper third of that depth, and it is not uncommon to find them within a few feet of the surface within the area of the lake that supports weed growth.
During the summer months, if water temperatures get too warm (typically above 68°F (20°C)), trout tend to stay in deeper parts of the lake, where the water is cooler and more oxygen-rich. They may be found feeding at depths ranging from 15 to 30 feet or more. In these deeper regions, they often target schools of smaller fish, such as minnows or shrimps, as well as various aquatic insects and crustaceans.
In the cooler months or during certain times of the day, trout may move closer to the lake’s surface or shallower areas to feed. This behavior is especially noticeable during low-light conditions, such as early morning or late evening, when they actively seek prey near the surface. It is also worth noting, that in cold water conditions trout often feed on shallow flats, because the sun’s rays warm them first.
What I wrote above mostly concerns typical rainbow, brown and brook trout. Some trout species have distinct feeding preferences and behaviors. For example, lake trout prefer to inhabit deeper water, where they predate upon shoals of baitfish like ciscoes and whitefish.
Even then, while they can venture down to hundreds of deep, they still typically feed loser to the surface, where sunlight supports a greater quantity and variety of organisms. There is typically not much to eat in the dark depths of a lake.
Factors that determine the feeding depth of trout
In this section, I will discuss environmental factors that help determine where in the water column trout are most likely to feed. In general, water temperature, food availability, and water velocity are the main factors that determine where a trout is most likely to feed.
Temperature
Water temperature is a big one. Trout are cold-blooded, when the water is cold they slow down, become sluggish, and rarely feed. When the water is too hot, they struggle to get enough oxygen so again they stop feeding.
Trout, try to seek out water within their most comfortable range. In warm summer conditions, trout often seek deeper water, because it is colder. In the winter, trout often move onto shallow flats because they are warmed by the sun.
It is often mentioned that trout can be found around the 53-degree thermal layer during the summer months. This rule predominantly applies to Lake Trout, rather than brown or rainbow trout which tend to feed across a greater thermal range. So, if targeting lake trout with a fish finder it is a good mark to remember.
In both situations, the trout still generally feeds close to the bottom, just in different depths of water. In very deep lakes, they might suspend off the bottom, especially when they are feeding upon plankton, krill, or plankton.
Food availability
When temperature allows, trout are likely to go where the food is the most available.
When the mayflies or caddis are hatching, you will find many trout feeding close to the surface. Likewise, they will surface feed when wind blown terrestrial insects are common. They follow the food to the surface.
However, outside of hatch periods or windy days, trout have little incentive to feed near the surface. The majority of their feeding activity tends to occur closer to the lake or river bottom, where they can find a more substantial food supply. Nutrients and aquatic organisms accumulate in these lower layers, often based around weed beds. This area provides a reliable food source for the trout.
Trout have a natural inclination to follow the food. They will position themselves where food is most abundant, whether it’s near the surface during specific hatches or closer to the bottom during other times.
Water velocity
Trout are lazy fish. They much rather wait for food to come to them than spend energy chasing after it.
So in rivers and streams. Trout prefer to feed where the current brings food directly to them. But, trout are lazy fish, they prefer to wait just out of the main flow.
Even in flowing water, trout usually wait close to the bottom where the current is slower. There they can wait while using minimal energy, only moving to intercept morsels as they drift by.
I have also noticed, the faster the water, the deeper the trout often hold. Right at the head of the pool, trout often position themselves tightly against the bottom.
While further downstream where the current is slower, the trout might be hanging midwater more actively drifting side to intercept morsels as they drift downstream.
Protection from predators
Trout feel safer when they are close to the bottom.
By hugging the bottom, they reduce the risk of being targeted by surface predators like eagles and bears. Additionally, this position makes it harder for larger fish to attack them from below. Being near the bottom provides a sense of safety for trout while they feed.
This behavior allows trout to take advantage of the surrounding environment for additional protection. They can seek shelter among rocks, logs, and aquatic vegetation, further reducing their visibility to potential threats. By remaining close to the bottom, trout employ a natural defense strategy that contributes to their survival in aquatic ecosystems.
What do trout eat from the bottom?
Trout have a diverse diet that includes various food sources found at the bottom of lakes and rivers. Some of the primary bottom-dwelling food items that trout feed on are:
- Nymphs: Trout consume the aquatic immature stages of insects like Mayflies, Caddisflies, Stoneflies, and Dragonflies. These nymphs live on the lake or river bottom until they undergo metamorphosis and emerge as flying insects.
- Snails: Trout feed on snails, which are plentiful in freshwater environments and provide a nutrient-rich food source.
- Aquatic Worms: Some aquatic worms or aquatic annelids, such as Tubifex worms, bloodworms (Chironomidae larvae), and various species of freshwater oligochaetes, are part of a trout’s diet when available on the lake or riverbed.
- Crayfish, Crawfish: Crayfish or crawfish are a preferred food source for trout, especially in river environments. Trout actively prey on these crustaceans, which often dwell near the bottom.
- Mussels: Trout prey on juvenile freshwater mussels, adding them to their diet when present in their habitat.
- Clams: Freshwater clams, similar to mussels, can be consumed by trout when they encounter them in the bottom sediment.
- Crabs: In certain regions, trout might feed on small freshwater crabs inhabiting specific water bodies.
How deep do trout feed?
Trout spend most of their time in the shallower parts of the lake, that is because the shallows receive more sunlight and other more biologically active. This means, wherever the sunlight can reach the bottom there is more food. This also means trout are more likely to be found feeding close to the shore than out in the middle.
This does not mean that trout can not survive at much greater deeps, both brown and rainbow trout have been recorded living as deep as 650ft while Lake trout live down to 1300ft. Although, at these depths, they likely feed on zooplankton in the water column and vertebrates that live on the lake floor.
While trout can live hundreds of feet down, that does not mean they are worth targeting down there. In warm water, summer conditions. Trout typically live around the thermocline, which depending on the lake can be around 50-60ft below the surface.
At cooler times of the year, trout typically move into the shallows, sometimes even as shallow as a foot or two of water.
Is it possible to catch trout feeding on Snails, Clams, or Mussels?
I have caught trout full of snail shells and seen photos of trout full of small clams. So it is certainly possible to catch trout that are feeding on them. In both situations, the trout were caught on more traditional fly and spinning patterns.
I have never seen anyone tie a mussel fly, but I know both Snail and Clam flies exist.
Snail flies are certainly a part of some trout fishermen’s arsenals. I personally find any chubby round dark fly makes for a reasonable snail imitation.
I have not heard of anyone targeting trout with a clam fly, they seem to be more the domain of Carp fishermen. But, in lakes with large populations of freshwater clams, they are probably worth a try.
How can spin fishermen catch bottom-feeding trout?
Spin fishermen have two options. They need to decide whether they want to try and replicate the natural prey of the trout, or just throw something obnoxious and hope they get a reaction.
If they want to try and “match the hatch”, I suggest fishing a worm pattern on a ned rig could be quite effective. The advantage of the ned rig is that it sits on the bottom and the worm just wiggles there.
Another option is to use either a split shot or a drop shot weight to cast out a selection of nymphs and try to present them in the path of the fish. I slightly prefer the use of split shot, while more difficult to cast, it does make for a smaller splash that is less likely to spook trout.
There is always the option to fish a large lure or spinner. If crustaceans are plentiful, a crayfish imitation can be effective. Just need to slowly work it along the bottom. If fishing in a tidal area, then consider fishing a crab lure in a similar fashion. Just try and match the size, and general appearance of the crustaceans where you are fishing.
Finally, it is often possible just to fish a normal lure such as a spinner or jerkbait, and hope the trout is willing to give chase. While trout spend a lot of their time feeding close to the bottom, they are constantly monitoring their surroundings. So other presentations can work.
Summary – Final words
Trout spend the majority of their time feeding on, or close to the bottom. This is the preferred feeding location for several main reasons, but for the most part, it comes down to food availability, temperature regulation, and avoiding the strongest currents.