It depends on numerous things that will determine what a fish will eat in the wild such as environment, season, and what type of fish it is.
Some common things that fish will eat in the wild include plankton, crustaceans, insects, and other fish.
As well as it being generally fascinating, it’s also very beneficial for an angler to know what kind of food the fish.
That they are trying to catch favors as this will make them much easier to catch if it is used as bait.
For most fish, half of their diet will come from protein with other parts of it consisting of carbohydrates and fats from algae.
Like us humans, fish use these groups to power their body the same way that we do with protein for strength, carbohydrates for energy, and fat for warmth.
Here are some common fish species and what they eat in the wild:
Pikes can grow to be quite large, stretching to a meter in length which makes them a scary predator for small defenseless fish.
The biggest pike recorded was caught in 1992 and weighed just over 21 kg.
They live in fresh waters such as rivers, streams, and lakes and like to eat a variety of things.
If a pike gets very hungry, it can even turn on its own kind and eat another pike, and with their large jaws and sharp teeth, they are not to be messed with.
Pikes are smart in the way that they use plants to hide in before moving incredibly fast to catch their prey which can be a fish, frog, or even a duckling.
They can eat anything up to half its own body weight so if it’s a big pike, it may even be able to take down a duck that has fully grown.
However, when the pike is young it will usually only eat small fish and invertebrates.
At this stage of their life, they are pretty much constantly eating and are known to eat about 3% of their body weight in food.
The walleye is another freshwater fish that belongs to the perch family.
They like to stick to cool, deep waters as they are sensitive to the light and can be found all around North America and Canada.
They are mostly carnivores and like to eat a range of things such as crustaceans, small fish, frogs, snails, and leeches.
They like to eat at night as they have great eyesight and are nocturnal, giving them an advantage over their prey.
If they are hungry though, don’t expect the walleye to be picky as it will take pretty much what it is given.
Their sharp teeth and strong jaws allows them to break through tough shells and have a style of hunting that is similar to an ambush.
Rockfish are saltwater fish that can be found in a range of different places such as the Bering Sea, North Pacific, California, and San Diego.
They can also differ in what habitat they live in as well, including rock reefs, shallow water, and the deep seafloor.
They are classified as omnivores and can eat a lot of different things in the wild such as crabs, plants, squid, eels, algae, and much more depending on what habitat they are in.
The way in which they hunt is by using rocks to hide behind before rushing out and taking their prey by surprise.
Rockfish can live up to an impressive 120 years and can grow to reach just over two feet in length and about 11 pounds in weight.
The carp is another freshwater fish that originated from Europe but has now spread to different areas all over the world over the years.
They live in pools, reservoirs, and rivers with a preference for slow-moving ones.
Carps are very opportunistic and if they see a tasty snack in front of them more times than not, they will take a bite out of it which works out quite well for anglers.
They are omnivores and are known to eat insects, snails, crustaceans, algae, worms, nuts, and berries, but this is just a small list of things that they will eat.
Carps can reach up to 30 pounds on average with a few notable ones reaching up to 100 pounds.
Which is partly due to the fact that they eat around 2% of their body weight in food with Asian carp eating up to 40% in a day.
Salmon can be found in both freshwater and saltwater which has an impact on what they eat.
Salmon in saltwater like to eat plankton which is a particular favorite for young salmon who have just left the river and entered the big scary ocean.
This is because plankton is small and is floating around almost everywhere in the ocean and require little hunting skills to catch.
Algae such as kelp and seaweed is another food that young salmon like to eat in the wild which is why salmon have such large levels of omega 3 fatty acids in them.
Once the salmon has grown up and gotten a bit bigger, they can move on to bigger foods that are a bit harder to hunt.
This includes other fish such as sardines, herrings, krill, and anchovies.
To summarize, fish can eat a whole lot of different things in the wild which is what allows them to grow so big.
You should also note that you are able to use a lot of these foods as bait either by replicating them with a lure or using the real thing.