Perhaps the most common activity that comes to mind when people hear the word "fish" is fishing. Whether with a bamboo pole or a state-of-the-art rod and reel, catching them for fun or food is the only way many people ever relate to fish. My parents and extended family were all avid fishermen (and women). My mother bow hunted spawning carp as a youngster, plug cast for bass, and bottom fished for catfish. My father often walked the local rivers for miles, knowing every hole and shallows, almost always returning with some delicious entrée. I can remember happily paddling him around in our canoe while he fished or fly cast from the front of the boat. Fishing was a wonderful excuse for spending long weekend days and nights out at a river or lake, enjoying not only the task at hand, but the company of good friends and family, the relaxing scenery, and the fascinating wilderness around us.
Even when I was very young, I was involved in the all-important collection of bait. Sometimes it was nightcrawlers. The technique was to go out in the yard late at night with a flashlight, walk very slowly and quietly, then grab the huge worms we spotted before they could pull back into the safety of their holes. The trick was to grab the end closest to the hole (not always very evident) so that the worm wouldn't slide out of our grasp completely or have enough leverage to break apart. There were other bait creatures that could be found by using a large seine in a river and shifting rocks to dislodge them into the current. This took two people, one for each side of the large net, and a moderate amount of cooperation to get the catch up on the shore for sorting. The huge array of animals ending up in our net was always thrilling. There were aquatic insects and larvae of myriad types, crayfish, leeches, small fish, and sometimes even turtles and tadpoles. The crayfish were often used for bait, peelers (individuals ready to shed their exoskeleton) 
and softshells being the best, although the tails of large ones also sufficed. The other bait relished by many fish was the hellgrammite, a wicked looking dark brown larva with painfully sharp jaws, usually growing 3 to 4 inches long. I learned very early how to handle crayfish and hellgrammites because pain is an efficient teacher.
Besides live bait, we sometimes used artificial lures as well. My parents had all the supplies for making fishing flies and had, especially in the early days of their marriage, done quite a bit of fly casting. When I was old enough to start exploring new art forms and materials, those beautiful feathers, delicate threads, and strange accessories were irresistible. Although I never got very good at fly casting, and didn't do it very much, my father would always try my latest creation and, if he happened to catch a fish on one of my surrealistically decorated hooks, he would praise its design to no end.
The fish that we caught were often for the dinner table. Cleaning them is not for the weak, as their skin is tough and cutting through bones and cartilage is quite a difficult job. Nothing on the fish ever went to waste, as we always had pet turtles that loved the leftovers, and also frequently buried the extra guts and bones next to the roots of prize vegetable plants. One suggestion to the uninitiated: fresh catfish roe does NOT taste like caviar.
The actual catching of fish by means of a hook and line was not always of interest to me, especially when I was small and impatient. I can remember catching a large bass (very exciting) and catching tiny sunfish one after another as fast as we could drop the hook (with or without bait) into the water (very entertaining). I occasionally used a fishing pole set out on the shore as a reason to sit around and do nothing. Much more often, I caught fish using a dip net or large seine.
During my childhood, we always kept aquariums and would usually populate them with native fish. Tiny bass, pikes, and gars were voracious and would eat anything smaller than themselves. Sometimes the size difference was not evident to me; fish of almost equal size would end up one inside the other's mouth. Little sunfish were only slightly less predacious, but very beautifully colored. There were also interesting bottom dwelling fish, like bullheads, catfish, madtoms, darters and stonerollers. Baby carp were easy to catch in the river shallows, and we were sometimes rewarded with seeing them, over a period of several days, turn into goldfish. Their color would start to change at one end and progress through their entire body, turning a dark golden brown fish into a bright orange one.
The only way to observe small fish was in an aquarium. Large fish, on the other hand, were easily seen in clear water. One awe inspiring memory was created when I saw 3-foot long carp swimming along the shore in preparation for spawning. They looked absolutely prehistoric and seemed to glide through the water without moving more than a slow swish of the tail. After a particularly hard winter, I later measured a dead carp found floating in the same quarry, just to be sure that the size was real and not a trick of the water influenced optics. Yes, it really was that big.
On a couple of occasions, fish were a little more forward with us. Sometimes, fish jumped into our canoe, which is always quite a surprise, but the 8 inch shad that jumped in my lap while I was kayaking really left an indelible memory. It's silvery scales seemed to rub off just like those on a butterfly's wings.
We would sometimes find dead fish that were just as interesting as the live ones. We often found the skulls and skeletons of long-nosed gar. They were considered trash fish and fishermen always threw them up on the bank. Their primeval anatomy includes ganoid scales and a long upper tail lobe. One winter, our favorite ice-skating lake froze over completely smooth and clear. Beneath a foot of glass-like ice, we could see dead sunfish floating in the eerie blackness, retaining their brilliant colors for the moment. Along a slough that was near the I&M canal, we once found the remains of somebody's catch: the heads of a catfish and a salmon. The salmon head had the distinctive curved upper jaw and nasty looking teeth of a mature male. The catfish head weighed 8 pounds (yes, really).
The most interesting dead fish can be found along the seashore. For a Midwesterner like me, all the saltwater fish are exotic and fascinating. From tiny creatures like spiny box fish and seahorses, to giants like the black drum, their forms seem endless. Cowfish retain practically their entire shape after drying out because of the bony plates enclosing most of their bodies. More than once, I've received a nasty wound from stepping barefoot on one of the bony spines of a spiny box fish, which litter the beach long after the flesh of the little beast has decayed. Some fish bones are so common, that they contribute to a fish's colloquial names; the craniums of marine catfish sport a cross-like design, giving them the name of crucifix fish. Fish like sea robins, goosefish, star-gazers, flounders, remoras and batfish have shapes so odd that nothing in freshwater even comes close. Memorable finds include several yard-wide stingrays, a 4-foot long mola mola, and an 8-foot marlin. Sharks and barracuda are always interesting because of their lethal teeth.
One time, while camping, we were rewarded with a windfall on a beach walk. A boat pulled away from the shore as we were approaching and we found that they had just left a pile of freshly caught flounder on the sand. Each fish had only a single filet removed, leaving a good portion of the meat on the bones, which we promptly gathered up. That gourmet meal was even more delicious because, well, everything tastes better when you are camping.
It is easy to see living fish while at the beach; just walk into the waves and look closely at the floating plankton. There are always tiny larval and young fish mixed in with the bits of seaweed and debris that is drifting towards the shore. When walking in shallow water, I always shuffle my feet in the sand to scare up the stingrays and skates, which seem to be so common along our Gulf shores. Along a calm ocean, I've marveled at the grace of a huge school of pelagic rays as they glide past like a flock of purple underwater birds. The first time I held a live seahorse that I had found in a shallow lake, it seemed simply magical that the little creature was curling its tail around my finger.
I had one really good scare while swimming. It was an almost deserted beach in Florida and I was holding an air mattress between me and the shore in about 4 feet of water. The slope of the bottom was such that the water remained about the same depth for a long distance before reaching a sharp dropoff and I was midway between the deep water and the beach. I noticed a stranger up on the boardwalk over the dunes waving at me but I didn't know why. I then turned around to see if anything was out farther, a boat perhaps. The water was crystal clear so it was easy to see a sizable shark quickly swim toward me from the deeper water, only to have it turn at the last minute, practically brushing me as it passed. I could feel the wave from its powerful stroke as I noticed that it was a bit longer than the air mattress that I was holding next to me. 
Before I took my next breath, I had jumped onto the float and stayed stock still until the very calm surf pushed me into shore (a perceived trip of inordinate length). I think I started breathing again sometime along the way.
While fish watching will probably never be as popular as bird watching, just the fact that they populate an entirely different world than ours makes fish seem almost alien. However, this is just the limited view of a land-dwelling mammal (me), who happens to know that, while insects rule our terrestrial kingdom, the much larger domain of the aquatic realm belongs to the fish.
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There are between 22,000 and 28,000 species of fish, more than half of all vertebrates. Over 40% of fish species live in surface freshwater which only accounts for .01% of the Earth's total water. |
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The largest living fish is the whale shark, at 60 feet. The smallest fish is a Philippine goby that is about ½ inch long. The largest living bony fish is the mola mola, or ocean sunfish, at 3,000 pounds and 10 feet, but the largest bony fish discovered so far was the Leedsichthys of the Middle Jurassic, at almost 40 feet in length. |
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A "sardine" is any small herring-like saltwater fish. |
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There are three types of fish: jawless (lampreys), cartilaginous (sharks and rays), and bony (all the rest). |
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Most fish are colorblind. |
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A fish that is catadromous hatches and spawns in saltwater but lives its life in fresh, such as eels. The opposite is anadromous, including salmon. |
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Fish have one of four kinds of scales: placoid are toothlike (sharks), ganoid are platelike (gars), cycloid and ctenoid are overlapping (most bony fish). The difference between the last two is that cycloid scales are smooth edged, while ctenoid are rough or comblike. |
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Fish are the only vertebrates with a two-chambered heart. |
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Deep water fish have less bone in relation to flesh; they can therefore endure higher pressures and also are flexible enough to eat a lot at a time during their infrequent meals. |
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Some fish have pharyngeal teeth, which are located in their throats. |
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Fish maintain balance with a pair of calcified nodules called otoliths that roll around inside cavities in their skull. These accumulate layers as the fish grows, thereby giving a good indication of age. |
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The fastest fish are pelagic hunters, like tuna and marlin. They can swim at about 50 mph for short bursts. |
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The lateral line of fish is considered to be a sixth sense and is sensitive to pressure waves and low frequency vibrations. |
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Aquarium fish are the most popular pet in America. |
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Electric eels can discharge as much as 650 volts and can grow to 10 feet long. |
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Because of the difference in saltiness between internal fluids and the water, freshwater fish don't drink but urinate profusely, while saltwater fish do the opposite. The exception seems to be sharks, which have flesh as salty as the water in which they live. |
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Larval flounder start out with eyes on both sides of their heads. Whether they migrate to the left or the right is determined by species. |