You may have heard a fisherman talk about the one that got away. In Florida there is a tale of some that got away - and then came crawling back. And it's a true story.
About 15 years ago, a Florida fish farmer imported some unusual-looking albino catfish from Bangkok, Thailand. Over there, the catfish were popular with fish farmers because they could live out of water for long periods and could be hauled to market in burlap bags still fresh for sale.
As it turned out, they had another characteristic which has landed them in a heap of trouble with Florida's tropical fish farmers and has spawned a laboratory research effort on them. The fish can crawl on land.
The fish's formal name is Clarias batrachus, popularly called the ''walking catfish.'' It has turned out to be an escape artist as well.
''They're heading north,'' says Paul Shafland, director of the nonnative fish research laboratory of the Flordia Game and Fish Commission.
They may crawl up to a mile a night, using pectoral fins and moving similar to the way a soldier covers an obstacle course by digging his elbows into the ground, says Shafland.
Their northward crawl began with their ''escape'' from a fish pond near Boca Raton. The fish can jump up to two feet in the air, easily banging aside the tops of aquariums and jumping out to crawl away, researchers say. Getting out of fish ponds was even easier.
Later another batch escaped a fish collection in Tampa. The catfish, which once numbered in the hundreds in Florida, today number in the millions, says Walter Courtenay, professor of zoology at Florida Atlantic University, who has been studying them.
The Boca Raton escapees have reached as far north as Melbourne in central Florida and have joined the Tampa escapees. They are now in the St. Johns River, which flows as far north as Jacksonville, Fla., says Professor Courtenay. How far the fish may go is speculative, both researchers say.
What worries them is that some of the fish are crawling back to the kinds of places they escaped from - tropical fish ponds, where they eat other fish.
''They may have done several hundred thousand dollars of worth of damage'' to tropical fish farms by crawling into private ponds and eating other fish, says Courtenay. Some Florida fish farmers have had to erect fences to bar the walking catfish, he says.
Ross Socoloff, president of the Florida Tropical Fish Farmers Association, says he is not worried, however. The walking catfish have had ''no real ecological impact on the state,'' he says.
As for Clarias, or the walking catfish, he is likely to be around for a long time. In laboratory tests the fish has lived up to 85 days out of water under warm and moist conditions and can crawl from one body of water to another, says Shafland. Thus it is suited to the periodic droughts and low water levels in southern Florida.