This supposed fact has resulted in numerous jokes, memes, and punch lines. It is the common- knowledge gem that any Joe on the street can tell you about our underwater neighbors. The fish brain has become synonymous with poor recollection, the humble, boggly-eyed bowl inhabitant unable to recall what was happening only a moment previously. But this is not a fair representation.
The current evidence suggests a cognitive ability within fish that sits way beyond our meager expectations. It transpires that fish are not only susceptible to Pavlov-like conditioning, but even within the parameters of their wilderness homes, are capable of astonishing feats of intellect. Gone now are the days of knowing the fish to be a shameless, brainless automaton, shunting from one position to the next like some syntactic stimulus/response robot, and in come studies of group cohesion and recognition, teamwork, Machiavellian intelligence and even basic problem-solving. All of this work meets stiff resistance from the world at large.
Chief amongst the detractors of fish intelligence are the angling community, who sometimes erroneously assume that advances in fish welfare will lead inexorably toward blanket banning of their sport. Fishing groups and advocates are so keen to protect their activities that any evidence that demonstrates piscine ability to feel pain is put down with hostility and derision, while at the same time, anecdotal reports claiming pain to be absent are seized upon by mainstream media, in scientific reviews and opinion pieces—often funded by angling bodies themselves. It is a hostile world in which to try to give fish some presumption of sentience.
Our own anthropomorphic tendencies are much to blame for the denial of fish intelligence, and not wholly unfairly. We accept sentience, and even ascribe salience, in those animals to whom we can relate. A dog owner will instinctively pick up on the signs of a poorly or downtrodden pooch. Cat owners can come to know their felines so well that the slightest movement or posture can communicate more than the sum of its parts. And this comes as no surprise. Humans have interacted with terrestrial beasts for millennia, to the point where there is a conscious mutualism between us. They appear to clearly feel pain as we do, they lick at wounds, they yelp in distress, they avert themselves from noxious stimuli.
Our relationship with fish has been less intimate. For the best part they are food, or trophies within domestic aquaria. Often our first experience of the life aquatic will be found wriggling on the end of a line, swayed by attractive bait and lured onto the point of a hook. At no time in our day-to-day lives do we engage in their world; never do we take the gonzo position of immersing ourselves within a shoal to see the interactions and struggles that reside.
This makes it all the harder for the uncommitted observer to accept the research and progress championed by the likes of Dr. Culum Brown, one of the foremost thinkers within the fish intelligence field. A little investigation into the scientific community will reveal books with titles like Fish Cognition and Behavior (Brown) and papers by researchers like Sneddon, Bshary, Earley, Wolf and other pioneers of this fast-growing field—all very serious and influential, gaining more and more credence with thinkers worldwide.
All aquarists will be able to recount tales of fish that recognize them. My own time as a lecturer in aquatics saw that fish learned to associate the blue uniform worn by those in the college livestock department with the providence of food. A hundred people could walk through that section daily without evoking a single response; but just one individual in a blue shirt would send fish dashing, mouths poked through the surface of the water, in soundless excitement at the prospect of dinner. One university even reports that their fish have developed a fondness for redheads, in testimony to the bright orange mane of the woman who for years provided their supper.
In more formal studies, we see remarkable feats of intelligence, comparable to behavior we consider the exclusive domain of “higher” animals. A striking point in case is that of the blind cave fish, Astyanax fasciatus. These fish have evolved for life as troglofauna, creatures immersed in perpetually dark subterranean environments. Here, locked away from light, eyes are of little value; the fish interact with their environment through the trial and error of touch. Yet Dr. Theresa Burt de Perera, of the University of Oxford, found that within a few hours in a new environment the cave fish had managed to spatially map out the terrain, and could henceforth avoid obstacles in their path.
The case for memory has even been made with what many of us consider the simplest of fish, the humble goldfish, Carassius auratus. Professor Caroline DeLong, of the Rochester Institute of Technology, has performed experiments on goldfish that involve relating a symbol to a reward, much like the anecdotal redhead mentioned earlier. Goldfish are shown to clearly discriminate among shapes and objects to select those that provide them with a reward—in this case black circles, which when touched result in a food “prize.” After a little prior conditioning and association, the goldfish goes for the rewarding design every time.