What Food Should You Feed Trout in Ponds? (Trout Food Guide)

Trout are some of the most economically valuable freshwater fish in North America and Europe. These energetic animals are sought after as sport fish and as sources of highly nutritious meat. Although many are caught in natural bodies of water, some types are increasingly farmed in private ponds to meet both local and international demand. These include rainbow trout (Oncorhynchus mykiss), brown trout (Salmo trutta), and brook trout (Salvelinus fontinalis).

The survival of trout, the rate at which they grow in ponds, and the nutritional composition of their meat are largely dependent on their diet and the ways in which they are fed. Water conditions also significantly influence how well they can convert their food into desirable proteins and lipids. Their physical health, general well-being, and their surroundings affect their metabolism. Their diet should thus meet their basic needs and be instrumental in keeping stress levels at a minimum.

When feeding trout in recreational and aquaculture farms, keep in mind that the amount with which you feed them and the suitability of the feeds determine how profitable it is to grow them. In some extensive types of ponds, trout need not be fed with supplementary feeds. The use of forage fish for trout is not always economical, however. Utilizing a commercial diet may be the best means of increasing food conversion rates in your pond.

Natural Trout Habitat and Sources of Food

In the wild, the feeding habits of trout are largely influenced by the type of habitat they find themselves in. Commercial diets may attempt to mimic the nutritional profiles of their wild-caught food. This is why it is important to go over their natural food sources and the environmental parameters in which they are most likely to thrive.

Most types of trout naturally occupy cool bodies of freshwater. Their colors and patterns may develop based on the characteristics of their surroundings. They usually favor streams and lakes with water temperatures ranging from 10 – 16˚C (50 – 61˚F). Some populations thrive best in large lakes with some form of connectivity to the sea, whereas some are fully landlocked and rely solely on freshwater and terrestrial prey items.

The food sources of trout at sea, in lakes, and in streams are highly varied. Those at sea may seek food from the water column or may feed from the benthos and zones with marine vegetation. Those in lakes may consume large amounts of zooplankton and smaller fish, whereas those in streams may attempt to obtain more of their food from the water’s surface or from banks where terrestrial animals may have fallen into the water.

Feeding Habits of Trout

The feeding habits of trout are affected by their position in the water column, the seasonal availability of prey, and their age. Trout are rarely ever considered fussy eaters, especially as they are often quite easy to bait. They go after what is readily available as long as it is alive and packed with protein. Invertebrates may comprise a larger portion of their diets than small fish, so they are not considered voracious predators.

Trout that are found feeding right beneath the water’s surface are usually quite small. These fish typically measure between 1.5 – 2 inches (3.8 – 5.1 cm). Despite their small size, they are able to feed aggressively on many insects that veer close to or float on the surface. These include terrestrial or semi-aquatic beetles, ants, mature mayflies, caddisflies, dragonflies, and stoneflies. These may also include any worms and small eggs that have fallen into the water from overhanging vegetation.

Trout that favor feeding farther into the subsurface are more likely to wait for sinking food items. They may feed on more small fish that are likely to hide in submerged vegetation. Those that are juveniles and have yet to reach mature lengths might feed on copious amounts of zooplankton, whereas those measuring more than 12 inches (30 cm) prey almost exclusively on smaller types of fish.

Able to feed on macroinvertebrates on the pond, lake, or stream bottom, trout have a diverse diet and can thus be lured with many types of bait. They will readily devour aquatic larvae, worms, shrimp, fully aquatic insects, benthic fish, and even eels. You can be certain that naturalized and ecological mature recreational ponds are likely to support the dietary needs of trout if these fish are stocked in conservative densities.

Commercial Feed Quality for Trout

Trout require a high protein diet to rapidly grow and reach harvest size. If you intend to rear trout in your pond for recreational purposes, you may not necessarily need to provide them with commercial feeds. If, however, you intend to make a profit off of them and have harvestable sizes of fish each year, you will need to consider supplemental feeding.

Large producers of fish feeds usually carry formulations that are specific to trout. These are mostly composed of high-quality proteins (which may come in the form of fish meal) and varying amounts of fats and carbohydrates. Trout, especially fingerlings and juveniles, will obtain most of their dietary needs from the protein component. Feeds made for young trout generally have a composition of about 50% protein and 15 – 20% fat.

For older trout, this protein demand is lessened slightly. Larger feeds would thus have a composition with 38 – 45% protein and less fat. Aquaculture ponds with intensive production outputs may stick to high-protein diets with about 18 – 24% fat. The best feeds are those which have highly digestible proteins and reduced ash content. These support the efficient conversion of feeds to fish mass.

If you’re currently in search of trout feed manufacturers, make sure to consider your intended production rate for your fish. If you require a high-energy diet for rapid growth, the feed formulation’s protein to energy ratio should be around 20:1. Note that formulations with higher amounts of protein may be harder for the fish to digest and may result in more feed waste. In contrast, those with lower protein contents may have excess fat.

Special Feed Formulations

Given today’s advances in fish nutrition and feed development, there are now many specialized formulations made for trout farmers with unique goals. Of course, these are much more expensive than conventional trout feeds. Fish farmers that intend to grow trout in a more sustainable manner, with respect to the sources of ingredients in their feeds and with the intention of minimizing nutrient-rich waste, should be able to find high-quality, low-phosphorus feeds.

There are now formulations with proteins that are supplied by a considerable portion of insect meal instead of fish meal. Fish fed with these feeds appeal to environmentally aware consumers who would like to reduce their food-related carbon footprint. There are also feeds with higher astaxanthin contents for trout farmers that wish to increase the intensity of their fish’s red to orange pigmentation. Special medicated diets are also available on the market and can be used to rehabilitate stressed trout.

Trout Feeding Practices

Many trout farmers wish to grow their fish as quickly as possible and in a financially lucrative manner. This requires taking into account how efficiently trout are able to assimilate the nutrients from fish feeds. It doesn’t follow that more feeds result in more meat as the amount converted is largely dependent on temperature and on the size of the fish.  

For example, smaller fish tend to have higher metabolic rates, particularly if they are reared in relatively warm water. This is due to their higher developmental demand for proteins and their poikilothermic nature (i.e. metabolic processes are sped up in higher temperatures). Larger fish naturally have slower growth rates and are thus unable to convert as many nutrients into body mass. Feeding them with more than the recommended feed amounts would result in more waste.

Pay close attention to the water temperature whenever you feed trout. As temperatures begin to cool, trout metabolic rates will slow down. If temperatures dip to below 3˚C (38˚F), growth may be arrested completely. This is why, in northern temperate zones, trout in outdoor ponds should only be fed with a maintenance diet through winter. The maintenance dosage should not go beyond 1.5% of the body mass per fish.

Commercial trout feeds usually come with a feeding guide that indicates what pellet size and feed dosage are best for a given fish mass and temperature. You will need to keep a record of the average size and abundance of fish in the pond to make sound approximations about their feed requirements.

Feeding Trout With Forage Fish

If you intend to grow trout in a natural and unfed pond, you’ll need to establish a self-sustaining forage base for them to feed on. Fertilized ponds with ample vegetation are generally able to support a small population of trout (50 – 100 pounds per acre) without the need for supplementary feeds. As the population size and average body weight increase, natural food sources may become significantly depleted. Trout may need to be harvested for forage fish populations to recover.

Minnows may be used as forage fish for trout. Note that stocking larger and more aggressive freshwater fish, such as bass, may deplete trout populations. Bass feed on fish that are smaller than them, so trout will naturally form a part of their forage base.

Best Time to Feed Trout

Trout ponds that are fed with supplementary feeds are usually equipped with automatic feeders. They may be handfed as well, but it must be noted that this method is quite tedious and demanding for large ponds. This is because farmed trout will need to be fed multiple times a day. Depending on the stage of their growth, trout can be fed anywhere from 3 – 10 times per day.

Feeding times should ideally be spread out. Trout can begin to feed actively early in the morning, temperatures permitting. They are usually most comfortable feeding in temperatures ranging from 7 – 20˚C (45 – 68˚F). At temperatures at the higher end of this range, they should be even more active. At temperatures lower than 45˚C, it may be necessary to reduce feeding times to just 1 – 2 times per week. At temperatures above 68˚C, trout may become visibly stressed and should not be fed. Feeding can be resumed at a rate of once per day once temperatures decrease.

If you intend to provide supplementary feeds just once per day (in the case of recreational ponds), aim to feed trout first thing in the morning. Keep in mind that intensively-farmed fish must be fed multiple times a day with a feed dosage that is recommended by the feed manufacturer.