Perhaps more than the people of any other state, Florida residents are attracted to the collection of bizarre pets. Tropical fish shops abound; a house without an aquarium is not a home. And Florida has seen turned loose in its wilds more exotic beasts, birds and reptiles than any state except Hawaii. The results have not always been happy. Just as Hawaii learned from its experience with the mongoose, and Australia learned from rabbits, so Florida is learning from the red-whiskered bulbul, the poisonous giant toad and the South American caiman that a wide-open immigration policy can be dangerous, especially in an area and climate where all things seem to flourish. Or is the state really learning? Gloomy biologists, worrying about the effects of strange animals intruding on the stamping ground of native species, think there ought to be a law against it all, but find little public outcry for one. As of the moment, the pet shop lobby has the situation well in hand. But now game fishermen—and fishing is one of Florida's chief industries—are beginning to worry. The native black bass ( Florida's largemouths are the biggest to be found in any state) is facing competition from the African cichlid and the peacock cichlid, which are something on the order of American sunfishes. But an even greater threat, perhaps the worst of all, now looms.
A year ago last March a boy fishing with worms in a canal near Palm Beach caught a very strange fish. It breathed air and was capable of walking, after a fashion, on land. Otherwise it looked like a catfish, whiskers and all, except that it had white skin and pink eyes. There are some 2,000 species of catfish scattered around the world and it took a little doing to pin this one down to the point of positive identification. Bob Goodrick, fisheries biologist of the Florida Game and Fresh Water Fish Commission, studied the fish, and Dr. Walter R. Courtenay Jr., ichthyologist and assistant professor of zoology at Florida Atlantic University, dissected it. Eventually the curious thing wound up at the Academy of Natural Sciences, Philadelphia, which identified it as Clarias batrachus, or, as we say, walking catfish. Furthermore, it was an albino of the species, which accounted for the white skin and pink eyes. A little research disclosed that an ordinary, run-of-the-mill walking catfish is not fantastic enough for the keepers of home aquariums in Florida, and so thousands of albinos—the first of them from Thailand, which also supplies us with Siamese fighting fish—were imported by the pet and fish shopkeepers. Catfish were going like hot fish cakes at 69� apiece when newspapers began reporting that they were a danger to the ecology of Florida. Then, so perverse is the human condition, the price jumped to 89�.
Many kinds of catfish have a way of being weird. There is a European variety (Silurus glanis) which is said to reach a length of 10 feet and weigh 400 pounds. It does not walk, but catfish of the Andes have been known to climb precipices. And walking is not confined to the Southeast Asiatic type found in Florida. An African catfish, which grows to a weight of 50 or 60 pounds, also strolls about when the spirit moves it. Then—and this has to be the absolute end in nonconformity—there is a Nile catfish that is white on its back and black on its belly. The reason: it swims upside down.
The catfish found in Florida may be said only out of courtesy to "walk." It moves more like a man crawling on his elbows. They have strong pectoral fins with spines on them which serve as anchors, and on these they more or less elbow their way forward, assisting their progress by sculling with their tails. On very dry land their skin may be scraped badly but it heals in two or three weeks. Sometimes, in walking under adverse conditions, they lose their whiskers (barbels) entirely but these are regenerated in a week, says Dr. Courtenay.
Once alerted to the dangers implicit in the presence of a walking catfish on Florida soil, the biologists began studying the beast with a kind of nervous intensity. They came to conclusions that are not encouraging. Goodrick and a colleague, Vernon E. Ogilvie, found that "the usual barriers [salt water, control structures, levees, etc.] which confine or control the movements of freshwater fishes do not apply to the family Clariidae. A fish with the ability and inclination to leave the water and 'walk' around is, to the best of our knowledge, unmanageable," they concluded.
"The individual or individuals responsible for introducing the Clarias catfish may have done the people of Florida a great disservice," they said. "It is quite possible that the Clarias may have a more detrimental effect on the ecology of Florida than any other group of fishes, including the piranhas."
Piranhas, whose importation is now-prohibited though pet shops have sold thousands in the past, have been reported present in the Everglades, but this has not been confirmed. They are, of course, those voracious South American devils, more deadly than sharks, a school of which can strip an entire animal, including man, down to a skeleton in a matter of minutes.
Well, a walking catfish can scare the hell out of a piranha. The catfish are extremely aggressive, though it is not true, as an excited lady reported, that one of them attacked her dog. Still, a specimen 13 inches long did kill another of equal size in a 70-gallon tank and so terrorized the other fish, both exotic and native, that, as Ogilvie and Goodrick reported, the fish "gave the Clarias a wide berth, the piranha being no exception."
The walking catfish is a most powerful jumper, capable of leaping four feet out of the water, which would be considered rather more than exceptional for a trout or salmon, and on land they are able to move at a rate of 20 to 30 feet a minute. They have not actually been observed moving overland for as long as a minute, since they are then hunting for such food as snails and pause from time to time to sniff the air or something, but that is their rate of speed. In addition to snails they are fond of freshwater shrimp, crayfish, frogs, tadpoles and, most importantly, small game fish—like baby bass.
The walking catfish "are so strong and slippery," Ogilvie and Goodrick reported, "that it is nearly impossible to handle them." Few would want to. Some have tried their flesh (the preference is for frying) and, with something less than enthusiasm, pronounced it edible, but skinning them is an ugly and difficult task and the odor can be offensive.