Can Trout Smell? Some Scents Attract Trout, Others Repel Them

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Man's hand holding a trout fish.

Yes, trout have a very acute sense of smell. They are able to pick up very subtle scents ranging from food, threats to their survival and even other fish.

I’m a fly fisher. I can’t remember the last time I fished for trout with bait. I don’t frown on anglers who fish with bait, but it’s just not my thing.

But anglers who fish for trout with live bait, salmon eggs, corn or even Powerbait have a distinct advantage over fly fishers. They can appeal to the incredible sense of smell that trout possess. 

We know fish can identify potential food sources through their sense of sight and their ability to see colors. But a trout’s sense of smell might be its most important sense. 

Not only can it use it to sniff out food or threats, but a trout also uses its sense of smell to hone in on its natal waters so it can return home to spawn every year. 

A Trout’s Nose

A trout has two “nares,” or nostrils on its snout. The olfactory organs can detect very subtle scents in the water. According to author John Merwyn, who wrote The New North American Trout Fishing, trout can pick up scents in the water in the parts-per-billion range. 

For contrast, the average human can pick up scents in the one part per million range. A trout’s sense of smell is likely much better than ours. 

Now, how can you use this information to catch more trout when you go fishing?

The Advantage of Bait

Dendrobena veneta earth worms for fishing and composting.
Using live bait also means you’re using scents from that bait to attract fish.

Obviously, bait anglers have a leg up on fly fishers when it comes to using scent to attract trout. Live bait, like worms, minnows and grasshoppers give off natural odors. These are scents that trout associate with food

But other odors work too. Garlic, for instance, is a proven trout attractor. So is anise oil, which is derived from aniseeds. It’s what gives licorice its flavor. 

Some bait and lure manufacturers use scents in their products. For instance, Powerbait comes in several fish-attractant scents. So does Gulp, a material added to soft-plastic lures. 

But, truth be told, you will probably attract as many trout with a good, old-fashioned nightcrawler as you will with any manufactured bait that you can buy over the counter. 

Fly Fishing Solutions?

Fly fishers rarely apply any topical scents to their flies. In fact, some flies are tied using materials that have been known to actually repel trout, like any petroleum-based distillates. 

So how can fly fishers beat this challenge? The first thing they can do is to try and remove any offending odors. I do this by taking a fly out of my fly box and trying to add scents to it that might be familiar to fish.

For instance, if I’m fishing a willow-lined trout stream, I’ll take a handful of willow leaves that have a sweet scent to them, and rub the fly down with them. Other scents that are common along trout streams work, too.

Sage is a good option. So is pine sap. In a pinch, I’ll even just rub the fly down with dirt on the stream bank. I’ll try anything to mute the scent of head cement or other astringents that might be found in the tying materials.

But there is a line for me and likely for most fly fishers. I don’t add attractants, like garlic or anise. I won’t dunk a fly in fish oil or smear worm guts all over it. If I’m going to do that, I might as well use bait, right?

Final Thoughts

Trout can and do use scents to identify food. But their very sensitive olfactory system is also used to identify threats and to navigate home to the waters where they hatched from eggs. 

Bait fishers definitely have an advantage over fly fishers when it comes to using scent to attract trout. Often, the bait used by anglers gives off enough smells to attract trout. But other scents, like garlic or anise can be added to bait to make them smell even better to fish. 

Fly fishers often have the opposite problem. While most flies generally smell “neutral” to trout, some flies are constructed with petroleum distillates that actually repel trout. 

For this reason, I often try to neutralize the smell of flies right from my fly box by applying something that occurs naturally near the water, like the smell from willow leaves or wild sage. 

But, the most important take-away information for trout anglers is this: trout can smell, and they can smell very well. Use this information in your fishing, and you’ll likely have more success. 

FAQs

Why is Anise Used as a Fish Attractor?

Anise has long been added to fish baits as a scent attractor. Not only does it smell good to trout, but it’s a source of nutrition, too, believe it or not.

Does Scent Work for Trout?

Some anglers swear that adding scent to lures or baits makes a big difference. There is no doubt that trout find some scents, like garlic, for instance, to be appealing.

Are There Smells Trout Don’t Like?

Petroleum distillates are known to repel trout. So, too, are chemicals found in bug spray, sunscreen, tobacco and hand lotion. 

How Can You Remove Smells Trout Don’t Like?

Try rubbing scents on flies that appear naturally in the water or near the stream. Some anglers even smear their flies with river mud to get rid of any unnatural smells. 

Chris Hunt Avatar

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