River vs. Stream: What’s the Real Difference?

Have you ever wondered whether there’s a real difference between a river and a stream? While fishing one day, I found myself asking exactly that question. My initial thought was that a river is just a bigger stream. That’s partly true—but it’s a little more complicated than that.

In the strictest sense, stream is a general term for any flowing body of water, while a river is simply a large stream. In other words, all rivers are streams, but not all streams are rivers. The point at which a stream becomes a river isn’t fixed—it’s somewhat subjective and often depends on regional usage.

A useful analogy is roads: a stream is like any road, from a small street to a highway, whereas a river is more like a major highway. An even better analogy, though, is a tree. Small headwater streams are like the tiniest twigs; as they join together, they form larger branches, and eventually a main trunk. In this sense, a river is the trunk of the tree, fed by an entire network of smaller branches upstream.

Hydrologists take a more systematic approach using the Strahler stream order system. In this system:

  • 1st-order streams are the smallest channels with no tributaries and are often headwaters.
  • 2nd-order streams form when two 1st-order streams meet.
  • 3rd-order streams form when two 2nd-order streams meet, and so on.

Using this classification:

  • Low-order streams (1–3) are what most people think of as streams, creeks, or brooks.
  • Mid-order streams (4–6) are transitional and are often locally called rivers.
  • High-order streams (7+), such as the Mississippi River (around 10th order), are large rivers.

So, who cares?

For anglers, this actually matters. Stream order correlates strongly with habitat type, water conditions, and fish communities. In many cases, the size and order of a stream are good predictors of the kinds of fish you’ll find there:

  • 1st–2nd order streams (tiny headwaters):
    Cold, shallow, and shaded; typically home to small trout and minnows.
  • 3rd–5th order streams (small rivers/creeks):
    More stable flow with moderate depth; commonly hold trout, smallmouth bass, and panfish.
  • 6th-order and higher (large rivers):
    Deeper, slower, and warmer waters; support species like walleye, catfish, pike, and largemouth bass.

As stream order increases, you generally move from small, cold-water species to larger, warm-water fish.

Species #25 and 26: River Chub and White Sucker

This afternoon I went to Rushford to try to catch Redhorse species and White Sucker at the Root River canoe drop-off on the south side of town. I used a simple bottom rig: 6 lb monofilament, 1/8‑oz sinker, 6 mm bead, size 10 barrel swivel, and about 18 inches of 6 lb leader with a size 8 hook, baited with roughly a 1/2‑inch piece of earthworm. No bites. I gave up after about 45 minutes.

I then drove to Preston to try for Brown Trout on the South Branch of the Root River. Because I was feeling a bit lazy I decided to stick with the same bottom rig for a while before switching to an inline spinner. I was surprised when I quickly caught a decent-sized, beautifully colored Rainbow Trout on the bottom rig. It put up a respectable fight.

A little later I reeled in a ~3-inch River Chub (Nocomis micropogon)—a new species for me—which gave no fight (not surprising given its size). I didn’t even realize it was on the line until I pulled it in.

River Chub

About 20 minutes later I caught a solid (~12-inch) White Sucker (Catostomus commersonii), also a new species. Interestingly, it put up very little fight given its size. The White Sucker’s lips look like those of someone who’s had a bit too much Botox.

White Sucker
White Sucker (close up of lips)

I never did get around to using the inline spinner before I had to quit for the day. Perhaps I would have picked up a Brown Trout if I had.

So far, in terms of fight relative to size, I would rank Bluegill, Smallmouth Bass, and Trout as the best fighters. Channel Catfish also fight well, but they’ve been larger fish, so that’s somewhat expected. The least impressive fighters for their size have been White Sucker, Bullheads, and Northern Hog Sucker.

A little reading suggests that bottom-feeding fish often don’t “fight” as dramatically on hook and line because they’re built for steady, near-bottom living rather than quick bursts of speed. Their bodies and behavior favor slow cruising and endurance, so instead of explosive runs or jumps, they tend to pull steadily and hug the bottom—resulting in a more stubborn but less flashy fight compared with fast-moving predator species.

River Chub are apparently among the most common fishes in North American streams and are important prey for larger fish. They are often used as bait by anglers targeting bass and catfish. Their presence is also considered a good indicator of water quality, as they are relatively intolerant of pollution, turbidity, and siltation, and typically require a pH of at least ~6.0.

White Suckers are bottom feeders that use their fleshy lips to vacuum up sediments and the organisms within them. They are opportunistic feeders, consuming small invertebrates, algae, and plant material. In turn, they are prey for a wide range of larger fish including Walleye, Trout, Bass, Pike, and Muskie.

Chasing Brown Trout – June Morning on the Zumbro River

My goal this morning was to catch Brown Trout. I started on the South Fork of the Zumbro River near Millville, MN, but quickly ran into a problem—finding easy access to the stream. After some searching without success, I decided to change plans and head to the Zumbro River at Zumbro Falls.

I began fishing with a #10 hook, a small split shot about 12 inches above it, and about a half-inch piece of earthworm (with a little left dangling). I cast about 45 degrees upstream and let it drift naturally downstream. The setup felt a bit too light—I had trouble casting any distance—and after no bites, I abandoned that approach.

Next, I added a small bobber about 1–2 feet above the hook, rebaited with worm, and again cast upstream. Still no action. At that point, I decided to move on and head toward Zumbro Lake.

Access there proved difficult as well, but about five miles downstream I finally found a good shore spot (44°14’00.3″N, 92°28’57.0″W). I switched tactics and tied on a small inline spinner (I think it was a Mepps), hoping it might entice a trout.

No luck at first—but after moving a bit farther downstream, things finally turned around. I quickly landed two average-sized Smallmouth Bass. They fought well, as they always do, and made for a fun finish to the outing.

Smallmouth Bass

I would have stayed longer, but work was calling, so I wrapped it up. Not a new species this time, but at least I didn’t get shut out—and the bass made the morning worthwhile.

Species #23 and 24: Black Bullhead and Northern Hog Sucker


This afternoon I returned to Northfield to try again for the huge Carp I failed to land Monday evening in the Cannon River tailwaters below Ames Dam. Once again, things didn’t go as planned in terms of targeting Common Carp—but I still managed to add a new species to my list.

Given how underpowered my medium-light rod and small hooks felt earlier in the week, I switched to heavier gear: a heavy rod, 30 lb braid main line, a 2 oz flat weight (which holds well in the current), 6mm bead, barrel swivel, and a ~20-inch 17 lb monofilament leader. I began with a 2/0 Octopus hook, then downsized to size 1. I tied the braid to the swivel with a Palomar knot, the swivel to the leader with a Trilene knot, and the hook with another Trilene knot. It was my first time using both knots, and I found it satisfying to learn them.

I arrived around 4:30 pm and fished until sunset (about 9 pm). The afternoon was mostly sunny, with a few light sprinkles late that I actually enjoyed. Fishing makes you very aware of the weather—the changing light through the evening was especially nice.

I didn’t catch a carp, but I did land two small Bullhead and a large, feisty Bluegill. The Bluegill fought hard; in contrast, with the heavy sinker and rod, I barely detected the Bullheads until reeling them in.

I couldn’t determine which Bullhead species they were, but I’ve since learned the key feature is the chin barbels: yellow bullhead have pale barbels, while brown and black have dark ones. Brown and black can be further distinguished by anal fin rays and coloration—brown are mottled with 21–24 rays, while black are darker and more uniform with 17–21. Tail shape and habitat provide additional clues. Next time I’ll pay closer attention.

[Update: the Bullhead was later confirmed as a Black Bullhead (Ameiurus melas) on iNaturalist]

Black Bullhead
Black Bullhead

As sunset approached, I felt some disappointment—not having caught a carp or added a species (Update: apparently I had caught a new species, a Black Bullhead with iNaturalist update). But on my final cast I hooked a modest fish I hadn’t even realized was on the line. My initial impression was that it was a Redhorse species, which would have been a new species. However, iNaturalist (confirmed by two observers) identified it as a Northern Hog Sucker—still a new addition.

Northern Hog Sucker

There’s a pub, Froggy Bottoms, right along the promenade by Ames Dam where I was fishing. People passed by on their way in, occasionally asking how things were going. One man was surprised I was targeting carp, given their reputation, but understood when I explained their size and fighting ability. I also admitted I was after them for my species list.

Northern Hog Suckers and Redhorse belong to the same family (Catostomidae). They aren’t especially attractive fish, but they play important ecological roles—moving nutrients, supporting food webs, and stabilizing benthic habitats. In many systems, they function as keystone species.

Carp, by contrast, belong to a different family. Although they look similar and share bottom-feeding habits, this reflects convergent evolution rather than close relation. Carp have barbels and more complex pharyngeal teeth and are omnivorous, whereas suckers lack barbels and tend to specialize on invertebrates.

In the end, it was a good outing. I added a new species—the Northern Hog Sucker—and deepened my understanding of both suckers and carp.

Speciation in Action: Cutthroat Trout and Black Bass in the U.S.

I recently spent a week fishing in the Southeast—Missouri, Illinois, Tennessee, and Georgia—and two weeks in Washington State. I caught Smallmouth and Alabama bass in the Southeast and Coastal Cutthroat trout in the Pacific Northwest.

Looking into these fish afterward, I was struck by how many distinct forms exist in relatively small regions. Black Bass (Micropterus) include numerous recognized species—Florida, Alabama, Shoal, Guadalupe, Redeye, and others—often confined to single river systems. The figures below illustrate the distinct ranges of the Florida and Shoal basses as examples.

Florida Bass range
Shoal Bass range

Cutthroat Trout, by contrast, are mostly classified as subspecies of Oncorhynchus clarkii: Coastal, Westslope, Bonneville, Yellowstone, Lahontan, Rio Grande, and more.

Why so many forms in such small areas?

The answer is speciation—the gradual splitting of one population into distinct lineages when groups become geographically isolated and adapt to different environments.


Cutthroat Trout: Speciation in Progress

For example, coastal and westslope cutthroat:

  • occupy different watersheds
  • have long been isolated
  • differ in life history (coastal fish can enter saltwater)
  • show distinct appearance and genetics

Cutthroat trout show this process clearly. As mountains formed and rivers shifted, populations became separated—some in coastal drainages, others inland. Over thousands of years, they diverged.

Coastal Cutthroat Trout range
Westslope Cutthroat Trout range

Yet they are still classified as subspecies, not full species—suggesting they are partway along the speciation continuum.


Black Bass: Same Process, Different Labels

Black Bass followed a similar evolutionary path, with populations isolated in separate southeastern river systems. But here, taxonomists have taken a more “split” approach, recognizing many of these lineages as distinct species.


Where to Draw the Line?

These two groups highlight a key point:

The difference between species and subspecies is often a judgment call applied to a continuous process.


A Practical Take

For my “100 species” project, I’ll count forms like Coastal and Westslope Cutthroat trout separately. Each represents a distinct place, strategy, and experience—regardless of the label.


It’s Lucky I Didn’t Rediscover Fishing Until I Retired

I’ve recently fallen in love with fishing—perhaps even become a bit obsessed. I love everything about it: learning how to catch fish, understanding the different species and their features, the thrill of the fight, the quiet of being outdoors, and even the meditative rhythm of casting and waiting. I also enjoy learning about rivers, lakes, and the seashore, and the opportunity fishing provides to travel to new places. Although I enjoyed fishing as a child, I set it aside for most of my adult life while focusing on a busy career and raising a family.

My fascination with fishing began around age twelve. My Dad introduced me to it and would occasionally take us out. My Mom nurtured the interest further by giving me a couple of Golden Guide books on fish and fishing, along with a subscription to a fishing magazine. I devoured them.

My parents also had a friend, Harold Kraus, who owned a large farm about 20 miles southwest of my hometown of Hays, Kansas. On his property was a roughly 20‑acre pond stocked primarily with Bluegill and Largemouth Bass. By the time I was 13, my Mom would drop me off there on Saturday afternoons, trusting Harold to keep an eye on me while I fished for hours.

One day Harold suggested I cast a lure beneath a large fallen tree along the shoreline. “You might find a big Largemouth Bass there,” he said. Sure enough, after a few casts, I landed a 3‑ to 4‑pound bass—an unforgettable moment.

By about age 16, tennis and other interests began to take over. Soon after, I left for college, then graduate school, medical school, and a demanding career, along with the responsibilities of raising children. Fishing became an occasional pastime at best.

Now, at 67 and nearing full retirement, I find myself returning to it with real enthusiasm. In some ways, I’m almost relieved I didn’t rediscover fishing earlier—I suspect I might have found it hard to get anything else done. It’s a wonderfully time‑consuming pursuit, in the best possible sense.

Lesson Learned #1: Make Sure Your Rod and Line Fit The Fish

I went to Northfield, MN this evening to try to catch Shortnose Redhorse, which are supposedly common in the Cannon River just below the Ames Mill Dam in downtown Northfield which is one-hour northwest of Rochester. Northfield is known for its two colleges—Carleton and St. Olaf—which add to the charm of the town.

Ames Mill Dam

My strategy for redhorse was to use a split-sinker rig with the weight about 12 inches above a hook baited with a nightcrawler, cast into the riffles below the dam. The key is not to use too heavy a sinker—you don’t want it sitting on the bottom when targeting redhorse.

I was NOT catching redhorse, but I noticed numerous large Common Carp roiling in the water just below me.

Curious, I decided to let my bait hang over the side, close to the bottom, to see if I might get a bite from one of them.

Pretty soon I hooked a decent-sized fish. Initially, I thought it might be a carp—which I still need for my life list—but it turned out to be another Freshwater Drum. Those darn Freshwater Drum seem to be everywhere.

Still, I kept fishing, hoping to land one of those large carp.

Before long, I did hook one—and it was a fighter. I managed to battle it for about 20–30 seconds before it slipped away.

Shortly after that, a boy of about 14 who was fishing with his parents hooked a similarly large—perhaps even larger—carp. Unlike me, he clearly had experience. He played the fish skillfully, walking up and down the promenade along the west bank of the river to control it. He fought it for about five minutes before it finally got away.

As the evening went on, I hooked two more very large carp. In both cases, the moment I tried to bring them in, they snapped my 6-pound monofilament line.

It became obvious that there was no way I was going to land these fish with a medium-light rod spooled with 6-pound test.

Ironically, I had just purchased a heavy rod for catching flathead catfish—but had left it at home.

So I plan to return to Northfield soon (perhaps this weekend), but this time better prepared. I’ll bring the heavier rod, along with a reel spooled with at least 20-pound test line. I’ll also need a long-handled net that can reach over the 3–4 foot wall that lines the river, since the water itself is another four feet below that.

Still, I’m excited—I now know where to catch large carp. I just need to bring the right equipment.

And of course, I’ll also be back to try for more redhorse.

Species #21 and 22: Brook and Coastal Cutthroat Trout

It is funny how my fishing plans never turn out as planned. This morning I was going to try to catch Largescale Sucker and Brown Bullhead fish and instead I caught a Largemouth Bass (not a new species for me) and a Brook and Coastal Cutthroat Trout.

I started by fishing at Rattlesnake Lake at about 6 am in attempt to catch Largescale Sucker fish with a bottom rig (1/8 ounce egg sinker, small barrel swivel, about 12-inches of four-pound leader, and size 6 hook with bit of earthworm). I got no bites and so by 8am I gave up and headed to Lake Alice in an attempt to catch Brown Bullhead. That might have been futile since I am not sure that was the right habitat to catch Brown Bullhead. Instead, I caught a small Largemouth Bass.

After about 45 minutes at Lake Alice I headed to Plum #1 River Access Point about five miles away on the Snoqualmie River thinking of bottom fishing for suckers. Again, I think misguided since I think it might have been better for trout. There was a beautiful side pool and I fished that with the same bottom rig described above. I kept on losing the rig to snags. Eventually I thought to myself this might be a pretty good place to catch a trout (and not a bottom fish) and so I tied on a 1/8 Kastmaster spoon lure (silver and red) and after about 5 casts I hooked a trout which fought me pretty well and turned out to be a beautiful Brook Trout.

Brook Trout

I tried that lure a few more times but then lost it to a snag. I then switched to a small white in line spinner and that led to no bites and was also eventualy lost to a snag. Finally, I thought, ‘why not try a bobber and worm in the pool?’ I set it up, cast it out, and within a minute hooked another fish. I wasn’t sure what it was, so I posted it to iNaturalist, and the AI identified it as a Coastal Cutthroat Trout. That was exciting, since I had been trying all week to catch that endemic species. About an hour later, someone confirmed the ID on iNaturalist.

Coastal Cutthroat Trout


So, overall, a very successful morning—and my species count went up by two.

Territory covered for the day

Species #20: Rainbow Trout

Got up early again—5 a.m. I haven’t been getting much sleep this week thanks to my fishing obsession. But you’ve got to strike while the iron is hot—I’m only in Washington for a few weeks before returning to work.

I hadn’t had much luck west of the Cascades (Seattle, Westport), so I hoped things might turn around east of the Cascades. One bonus: far less traffic. My main targets for the day were trout (rainbow, steelhead, and brown) and pikeminnow.

I started at Lavender Lake, about 10 miles west of Cle Elum, since Luke had caught a lot of rainbow trout there a week or two earlier. On my very first cast—using a 1/8-ounce blue-and-silver Kastmaster—I hooked a fish, but it came off. I fished for another 30 minutes with various lures and got no bites, even though I could see fish in the water.

So, I headed to Ellensburg to pick up fresh bait—earthworms, which I know rainbow trout love. It took a frustratingly long time to find a place that sold worms, but I eventually found some at Bi-Mart. A guy I know (Copilot) suggested Mattoon Lake on the southwest side of Ellensburg as a nearby trout spot, so I gave it a try.

The lake had a nice pier. Even though I now had worms, I stuck with the Kastmaster for a few casts since it was already tied on. On about the fifth cast, I got a strong bite and landed a modest-sized Rainbow Trout (Oncorhynchus mykiss).

A man in his 40s who had been fishing from a small boat came in just as I was landing the fish and congratulated me. He then began fishing from the pier. He told me about a “foolproof” rig an older gentleman (around 70) had shown him—a drop-shot setup with a pencil sinker at the end and a small artificial bait tied above it. It seemed to work for him, but (not to be smug) I was catching fish at a much higher rate. I landed five rainbow trout in about 30 minutes.

After the fifth fish, I decided to move on in search of other species—specifically brown trout and pikeminnow. As I left, I wondered if the others were puzzled why I would walk away while the fishing was so good. In retrospect, perhaps I should have stayed—those ended up being the only fish I caught all day.

From there, I drove down the somewhat austere but still beautiful Yakima River Canyon, hoping to find cutthroat or brown trout. I stopped at a few pullouts but didn’t get any bites. After exiting the canyon near Yakima, I went in search of backwaters along the Yakima River, targeting Northern Pikeminnow—a species I hadn’t caught before.

Northern Pikeminnow are widely disliked because they prey on salmon eggs and harm salmon populations. In fact, there’s even a bounty program that rewards anglers for catching and removing them. Despite that reputation, I was interested in adding one to my list.

I spent the afternoon trying to access suitable backwaters, but access proved difficult. Hopefully I’ll have another chance to try later this week.

Fishing at the Westport Pier

After breakfast, we headed to the Westport pier with our bucket of freshly caught ghost shrimp. It was sunny, but quite breezy and a bit chilly—though still comfortable enough for fishing. We started around 11 a.m.

We used size 2 and 4 hooks, and both fished mostly with a hi‑low rig baited with ghost shrimp. Luke added small floats to the leaders on his rig, which seemed to work very well.

Luke ended up catching eight fish in total, while I unfortunately caught none. A bit of a bummer for me—but I was genuinely happy to see Luke have such success. He kept five of the eight fish, choosing the ones he felt were large enough: two Striped Perch (Embiotoca lateralis) and three Pile Surfperch (Phanerodon vacca).

Striped Surfperch
Pile Perch

That evening, Luke cooked the fish for dinner, and they were excellent—fresh, delicate, and very satisfying after the morning’s effort.

Although I was disappointed not to catch a fish myself (I did get a couple of bites but could not hook the fish), I was now confident that I understand how to catch these fish and would expect to have better luck next time. I always try to look on the bright side! Over the course of the weekend, I learned a great deal about surf fishing—hi‑low rigs, braided line (which I had never used before), ghost shrimp, and the importance of location and timing.