Trout fishing is filled with scenarios and situations that rarely have one right answer. How to best fish for trout? When to fish for trout? What gear to use for trout? These are all questions with answers that are dependent on the angler. One of the most controversial and confusing questions people ask is how to tell if a trout is stocked or not.
The truth is that there isn’t one way to always tell if a trout is stocked. Many experts say that a more “rough” looking fish is often stocked, or fish with dull colors may also be stocked. These factors, along with several others, can help in the process of determining whether or not the fish are stocked, but it isn’t a guarantee.
In order to help you determine whether or not a fish is stocked, pay attention to the following few things! Remember, there are always exceptions to the norms.
Where the Fish was Caught
One of the major factors anglers can use to tell whether or not trout are stocked is the location you’re catching them. For example, if you’re fishing a few hundred yards downstream of a hatchery, and you start landing fish, you’re likely landing stocked trout. They may not have traveled overly far and found a spot to reside.
It’s also possible to determine whether or not the water you’re fishing holds stocked fish. Some quick research on a state’s DNR or Game and Fish website will tell you if it’s stocked and when it was stocked. Plus, it’ll often tell you the exact type of fish that was stocked in the water. If you land one of the fish that was stocked, then the color and size will help you determine if it’s wild or not.
Fish that are miles and miles away from civilization and hatcheries may often be wild. They’ve found opportunities to mate and repopulate on their own without the help from the state. Certain stocked trout will travel miles and miles up or downstream, but generally, they won’t move terribly far. Some holdover (fish that were stocked in previous years) trout will travel numerous miles throughout their lives, but not always.
Rivers all across the United States have populations of both wild and stocked fish. States generally don’t want to have to stock waters if it’s not necessary. They’d prefer to let the trout populations become wild.
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The Color of the Fish
The color of the trout you catch is also a big giveaway as to whether or not the fish you landed is stocked or not. Most hatcheries are feeding their fish with pellets, so they aren’t eating some of the more natural resources that wild fish are eating. As a result, they generally have a more dull and basic color pattern.
This is especially easy to tell in brook trout. A wild brook trout will likely have bright greens and orange colors all over its body. A stocked brook trout will be a basic green color with smaller yellow spots. The colors will likely not be nearly as vibrant.
Food like shrimp, insects, worms and smaller fish all play a factor in helping a fish develop a more vibrant color pattern. Plus, being subjected to the natural conditions of the lake, river or stream will also add to these colors. Wild fish aren’t living in a controlled environment, so their DNA is able to fully develop without any inhibiting or limiting factors.
The Condition of the Fish
Perhaps the most believed hypothesis on how to tell if a fish is stocked or wild is that stocked fish look more “beat up” and “rough” than wild fish. Stocked fish are packed tightly in tanks and sections of water with tons of other stocked fish. Stocked fish don’t have room to move around and live in their own area.
They’re rubbing up against other fish as well as rough surfaces like concrete, so they may not fully develop their fins. Dorsal fins and tail fins on stocked fish may be shorter or not there at all. Plus, stocked fish may have had their fins clipped for different research purposes.
At times, larger stocked fish will swipe at some of the smaller fish to establish dominance. These bites can cause scarring on the bellies or sides of the fish.
These injuries that stocked fish have don’t always fully heal, so if you land a fish that has scars or missing fins, it’s safe to assume that it’s a stocked fish. Combine these injuries with a duller color palette as well as the location you landed them and it should be able to help you make a somewhat educated decision.
The Size of the Fish
When stocked fish are first released into the wild, they enter the water with a high amount of fat. They look like they had a long winter of feeding and didn’t have time to prepare their body for their summer beach vacation. They possess a pot belly that’s filled with all of the nutrients they got from the pellets.
Stocked fish didn’t have to do any traveling to find their food, so there was no way for them to slim out and harden in the hunting process. A recently stocked fish will look quite heavy. Hatcheries do their best to fatten up the fish as quickly as possible before they’re released.
Wild fish are slim and hardened from having to hunt and search for their food. Plus, they’re eating things like insects, crustaceans and smaller fish that are higher in protein and are generally more nutritious than pellets. Wild fish consistently work hard to find enough food each day, so they don’t have the ability to sit and wait around for a good meal to come their direction. This constant movement slims them down to a normal size.
If you’ve ever witnessed fish be stocked in a pond or stream and immediately targeted them, you’ll notice that they almost never eat your flies or baits. Stocked fish have to learn to feed themselves and it takes a while for them to realize that if they want to eat, they have to find the food themselves. This process of learning how to feed themselves generally takes a few weeks.
Stocked fish lack the aggression and fierceness of a wild fish. They learn what it takes eventually, but if you’re presenting your flies perfectly to fish and they aren’t eating, it may be because it was recently stocked.
Wild fish are aggressive and have the “normal” tendencies of trout. They’ll ambush their prey, feed on dries during hatches and look to eat streamers that are drifting through pools. While wild trout aren’t predictable, they do have somewhat consistent feeding habits. A properly presented fly or bait is likely enough to get them to strike.
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Talk to An Expert
The most useful thing I’ve found to help me answer whether or not a trout is stocked is talk to an expert. If I’m near a hatchery or run into a game and fish employee, I’ll show them some pictures I’ve taken on my phone and ask them the question. Generally, they’re more than happy to share their expertise and give me a better idea of how to tell whether or not the fish is stocked.
I’ve found that stocked fish and wild fish look different in almost every stream and lake I fish. The locals have given me great advice on what to look for in their physical characteristics as well as their feeding habits. I’ve picked up on many tips and tricks throughout the years.
At the end of the day, catching trout is exciting. While many anglers prefer to catch wild and native trout, stocked trout are still a blast to land. If you use the information like where the fish was caught, the color schemes, overall condition, the size and the feeding habits, you’ll be able to better understand if the fish was stocked.
Take good care of these fish, and feel free to take pictures and ask local game and fish employees or workers at a hatchery. They’ll be able to give you a better idea if the fish is wild or stocked.
Danny Mooers is a high school English teacher in Arizona with a love for fly fishing. Growing up in Minnesota gave him the opportunity to experience all types of fishing and grow his skills. After living out in the Western United States for several summers in college, his fly fishing obsession grew. Having the opportunity to share in his passion for fishing through writing is a dream come true. It’s a lifelong hobby and he strives to make it understandable for people of all skill levels
More Info and Sources
- Wild or Hatchery Trout? – https://dwr.virginia.gov/blog/wild-or-hatchery-trout/
- Native and wild – https://www.tu.org/magazine/from-the-president/native-and-wild/
- Brook Trout – https://www.ncwildlife.org/Learning/Species/Fish/Brook-Trout