OK... here's a story about some potentially "smart" bass...
Several years ago, while shore fishing a small public res, I spotted four large LMs holding along a stretch of shoreline. This was late June –past the spawn. A couple other anglers, heading out, said that "those big ones wouldn’t bite anything".
So...were these “big ones” just smarter?
I approached quietly, but somewhat visibly, and tried several things, including a 4” wacky’d finesse worm, a plastic craw, and a swimming worm, to no avail. I noticed though that when I approached, each bass reacted to my presence, but subtly. Their erect fins would sag a bit, and they’d drop a bit lower in the water column –doing what “head-hunting" brown trout fishers call “sulking”. They saw me, and they sulked. And they wouldn't bite.
So… I gave them a short rest, and then rotated back through each fish. This time, after having seen them sulk at my presence, I approached low to the water’s edge, and then kept hidden behind shoreline brush. Casting was difficult from behind bushes but the bass did not see me and did not sulk. And I caught three of the four! Two tipped up for the swimming worm on the first cast, like a trout coming up for a dry fly. Number three took the worm on the second cast. She was interested but turned away on the first, and took the worm killed and twitched on the second. The fourth had moved and spotted me on my attempted approach and, apparently having had enough, she vacated. The bass I lipped were two 19s” and a 20”. These were big fish in this water.
Were they smarter than other bass? Tough to say. I can say that they were easily alarmed, as most bass in public waters often are, esp on bright days. If any of these were spookier than others that day, I couldn’t say. I feel I can say that some bass are spookier than others, and although this can be an individual personality trait, it can also be ecological in nature. Male bass guarding a bed full of fertile eggs, and spiked on testosterone, may be the most difficult to spook. Immature bass (and deer) can be “dunderheads”. They can’t perceive as far as larger bass, have less experience with the environment, and live in high competition for food. That’s a recipe for a Darwin award. And there are lots of other things that affect a fish’s spookiness.
In general, do fish have "intelligence"? I’d say, yes. But, that comes in degrees. In working on my just released documentary (on the development of behavior in largemouths) I conversed with comparative cognitive scientists on various things “intelligence”, and the general consensus was this: "Intelligence" is ancient, and widespread. And the comparison of animals —including fish— with humans, is a matter of degree, not kind. Essentially, our roots run deep.
We often ascribe “intelligence” to the fish we pursue. Brown trout have been called the "wiliest of trout". Carp fishers will say that they pursue the most intelligent fish (and I've been one of them). It's easy to shoehorn human perspectives onto other creatures —to be anthropocentric— simply bc... that's what we have to work with! After coming to understand the social behavior of mule deer, I came to see that they succumb to the very same bias! Which I called “cervo-centrism”. I've been able to get deer accustomed to me, and they then begin to treat me… like other deer. I realize that they cannot do anything else. I'm either a predator, nothing of interest, or… another deer. What’s a little strange, and exposes something of their mental processing —their impressionist painting!— is that I’ve done this in camo, street clothes, and blaze orange! Are they stupid? No. They are deer.