As water cools in fall, catfish follow the oxygen, not just the temperature: once a lake's surface layer cools enough to sink and mix with the bottom, water that was unlivable all summer opens back up, and catfish that were boxed into a narrow band near the surface can finally spread out and go deep. In rivers, that same cooldown sends catfish downstream into the deepest holes they can find, where they'll spend the winter. Either way, fish structure and transition zones -- channel bends, riffle-to-pool breaks, humps near a channel -- rather than the open flats that produced all summer.
Why fall opens up the deep water
Missouri's MDC explains that a pond or lake stratifies into three layers over summer: a warm surface layer, a thin transitional thermocline, and a cold bottom layer called the hypolimnion. Decomposing plants and animals use up the hypolimnion's oxygen so thoroughly that MDC says "by mid-July this layer may be completely devoid of oxygen" -- fish simply cannot survive down there. When fall temperatures drop toward 50 degrees, the surface layer cools, gets denser and sinks, and wind finishes breaking down the thermocline, causing what MDC calls "complete mixing of the water column." Once that turnover happens, the whole lake is oxygenated top to bottom again, and catfish that were held near the surface all summer can use the deepest water in the lake.
Where to find them
In rivers, Iowa's DNR says channel catfish "move into the deepest holes of a river in late fall to over-winter," and describes them holding around "riffle areas just above pools, cut-banks, snags, rocks and other submerged structures" rather than open water. On lakes and reservoirs, look for the same idea in miniature: the deepest hole near a creek channel, a dam, or a steep bank, especially right after the first good cold front turns the lake over. Fish won't be as aggressive once the water is cold, so slow down and work a spot thoroughly instead of covering as much water as you would in summer.
What they're eating
Iowa DNR notes catfish diets shift as fall sets in: "more fish is eaten along with aquatic invertebrates and terrestrial insects," and frogs become an important food source "as they move into streams before winter." Rising water from fall rain helps too -- DNR says high flows "often provide more food for channel catfish to eat by flooding terrestrial areas." Scent still matters as the bite slows down, which is one reason a bait enhancer earns a spot in a fall catfish box.
Common mistakes
Fishing the same shallow flats and open water that produced all summer is the biggest one -- once turnover happens, the fish aren't held there by oxygen anymore and they've moved to structure and depth. The other is fishing too fast: cold water slows a catfish's metabolism, so working a hole patiently beats repeatedly moving on to the next spot.
Shop the gear
- Katfish Country Dragon Gliders -- weights for dragging and trolling baits for catfish, useful for working a deep hole or channel edge thoroughly instead of guessing at one spot.
- Snowball's Bait Tonic StankZapp -- a catfish bait enhancer for scent when the bite slows down in cold water.
Frequently asked questions
What water temperature triggers fall turnover?
Missouri's MDC says turnover begins as surface temperatures drop toward 50 degrees Fahrenheit, cooling and sinking until the whole water column mixes.
Do catfish feed less once the water turns cold?
Yes. Iowa's DNR notes catfish become less aggressive once temperatures drop, so a slower, more thorough presentation usually out-produces covering a lot of water.
Is deep water the same in a lake as in a river?
The idea is the same -- find the deepest, most stable water nearby -- but rivers concentrate catfish in specific wintering holes, while lake catfish spread across whatever deep structure near channels, dams or steep banks turns over first.
Do all catfish species behave the same way in fall?
Channel catfish are well documented moving into deep holes for winter. Flathead and blue catfish are less studied for this exact pattern, so treat structure and depth as a starting point and adjust to what you find on the water.