Randy(308) sent this article from the Houston Chronicle.

If you are what you eat, gafftop catfish are Dyson vacuums.
Early results from an ongoing study of the diets of predator fish in Texas bays indicate the saltwater catfish with the long wispy fins and the liberal mucous coating on their bodies may live up to the unflattering name many anglers give them. These “snot sharks” may indeed be the most indiscriminate, opportunistic predator in the bay.
“It's really pretty amazing some of the things gafftop eat,” said Mike Stahl, a Dickinson-based coastal fisheries biologist with Texas Parks and Wildlife Department. “It looks like they'll eat just about anything they can get in their mouth.”
Coastal fisheries crews conducting gill net samplings in Galveston Bay remove digestive tracts of a selection of the fish they capture and bag them with identifying codes.
The process gives fisheries managers insight into the prefer-ences and importance of forage species to predator fish such as speckled trout, red and black drum, flounder and gafftop. With the addition of gill net samplings on open-water reefs, as well as the long-running shoreline-based gill net surveys, researchers look to compare the diets of fish captured in the different habitats.
The “gut checks” of gafftop have produced some interesting contents.
Gafftop are much like other bay predator species, feeding primarily on forage fish such as menhaden, croaker, spot, mullet, bay anchovies and other small finfish. And like most other inshore predators, they also eat eels, shrimp and marine worms.
But gafftop don't stop there. The fish, which usually weigh 2-8 pounds, seem to not be afraid of attacking larger and less vulnerable creatures.
“We've found huge Gulf toadfish in gafftop guts — I mean big toadfish,” said Bill Balboa, Galveston Bay ecosystem leader for TPWD's coastal fisheries division.
The well-named toadfish (sometimes called oysterfish), with their large heads and truculent behavior (they're aggressive beasts that will inflict a nasty bite), seem unlikely gafftop victims.
Gafftop guts also have yielded large blue crabs and stone crabs, both of which can also put up a good defense. Perhaps the strangest items found in gafftop guts have been birds.
“We found a whole bird — it was identified as a rail — in one,” Stahl said.
But maybe the most telling insight into what gafftops will eat is tied to their relationship with their smaller, more abundant and almost universally loathed relatives — the hardhead catfish.
“Gafftops do eat hardheads,” Stahl said. “They are about the only thing that will eat them.”
That insight alone should raise gafftops' standing among saltwater anglers.