How to ID types of Fish with your Ice Fishing Flasher
How to ID types of Fish with your Ice Fishing Flasher 1

Of paramount importance to any hobby is knowing what you’re working with.  Just like a golfer doesn’t take a shot without knowing wind speed/direction, distance to the green, or pin location, you’ll probably do a whole lot better at this ice-fishing thing if you know what species just showed up on your sonar.  Each species has differing biology, behaviors, and ultimately, bite-triggers, making the game much easier to play when you’re armed with species by species knowledge.  While “Fish ID” is not a novel concept from the ice fishing finder end of the world, the best any graph has mustered to-date is simply showing marks as small, medium, or large fish, often in varying degree or fashion depending on a number of factors.  Underwater cameras are another way to get after fish speciation, but what if you don’t own one, you’re hole-hopping, or you’re dealing with camera-shy fish? 

Enter Tony Roach, a man who has seen just about everything that swims on a host of ice-fishing sonar units.  “That’s a walleye,” he confidently announced while staring at his MarCum M1.  “See it belly-to-bottom, then come up, then drop down.  It’s done it about three times in the past 30 seconds.”  Eventually, Tony connects, bringing a particularly goldeneye up on a panfish jig of all things.  How did he know it was a walleye, when we had landed nothing but gills the prior 10 hours on ice?  More importantly, what are the tell-tale signs, species by species, that will help us determine what we’re fishing for, and ultimately what bait to present and how?  Let’s answer some of those questions.

Fish ID For Your Flasher

First and foremost, there’s no substitute for seeing multiple varieties of fish in a host of depths, structure, and cover to help you accurately ID a sonar mark once you see it. These are generalities, made to help you start looking for cues to tip you off to fish species, such that you can present the right bait, the right way to them. That said, there’s a few guides you can use to get started.  If your sonar is worth a darn, big marks are big fish, small marks, often denoted by colors other than dark red, are small fish.  If small fish look big, and big fish look the same size, it’s time for an upgrade.  Use zoom mode if you can for the depth and application you’re fishing to get the most resolution from your flasher possible.  This is especially important for fish that hang on or near bottom like walleyes, and the bottom-zoom feature on Tony’s M1 was paramount in providing the ID he did. 


Crappie targets are often a function of the depth you’re fishing, and move slowly and methodically, usually in large schools suspended over deeper water.  “Those things grow bigger and smaller on the MarCum as they mill around down there,” Tony notes, “and they usually show up at the same level as the bait or just below if the screen was previously clear of fish.”  Usually, schools are segregated, so large marks will mean large crappies for most natural lakes.  “Some days, bigger fish in the school feed above the rest, but more often you’ve got to punch down and past those smaller more aggressive crappies to get to larger fish.  The best part is that the marks don’t lie.  Big marks are big fish,” says Tony.


Bluegills are probably the easiest to ID, especially bull gills.  They tend to emerge on your sonar near bottom, and will almost always slowly rise to your bait, stopping mere inches away to study it, making you guess the entire time whether or not they sucked in your offering, or are still staring it down.  If you swing and miss, they’re gone, rarely if ever to return.  Even if they charge the bait and are extremely aggressive, they’ll almost always still study the bait longer than most species will.  Smaller versions of the species do look small on sonar, whereas bull gills can be mistaken for bass or larger predators if studying just the size of the mark alone.  Either way, jigging too aggressively, especially as the fish closes can also get them to leave quickly. 


Speaking of bass, they typically show up at the same level as your lure, making the mark from your bait “grow” exponentially in size.  Their attitude in winter is often ho-hum, so think bull gill mark, only larger.  As a bass inhales the bait, the bite is slow, soft, and causes the rod tip to generally sink a good deal.  Seconds in, you’ll know what you’re dealing with, and can adjust for additional fish that look and act the same way throughout the day. 

Northern Pike

Pike show up where they please, and are often very large marks due to their length.  Especially a large mark that appears well above your bait, anywhere in the water column, tends to be a pike in most Midwestern waters.  In shallower water, say under 10 feet, they can come in so fast that you barely have time to see and/or react to any strike.  Expect them to do the unexpected, and have your drag set!


Walleyes are another easy one, often showing up connected to the bottom and appearing as if it just got ever so slightly shallower.  Roach, a particularly astute walleye angler mentions, “Eventually, that mark separates from bottom to come up to your jig, and either hits, or does not.”  The retreat and re-appear here are key to species identification here, as walleyes very typically do the “yo-yo”, up and down trick a few times before committing and hitting unless they’re very aggressive.  Dropping the bait into the bottom, playing keep-away, and generally being a bit more aggressive with your jigging stroke can be extremely effective. 

No matter the species, knowing a few things about their habits and what to look for on sonar makes playing the game more fun.  Those details, once you know what to look for, can make all the difference, turning good days on the ice into great ones by catching more fish.

As you prepare for the season or your next trip out, check out this article about Ice Season Preparation.

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