A couple of paragraphs in the middle of the description seem to be describing a different trope;
"In a more general sense, an animal that ought to be considered easy prey, yet it is also a vicious creature that attacks you instead, succeeds in biting you and leaving a nasty scar (sometimes despite having no teeth!). Oh, and it's darn near impossible to kill no matter how hard you beat on it, or how many bones you break.
Maybe it's a Killer Rabbit, Evil Squirrel, or a Rabid Raccoon, or the actual evil Catfish himself (Several shows will have a whole episode about an evil vicious Catfish), but if it's an animal that should be easy prey, but turns into a Moby Dick-style Animal Nemesis you've sworn to kill or die trying, you're probably dealing with The Catfish."
While I agree Moby Dick would probably fit this trope (it's a giant fish with a reputation for being a giant fish), I don't see how say, a Rabid Raccoon could reach the level of notoriety to qualify, nor have multiple people aspire to catch it (if I'm reading the trope right?). Could we just scrap this section, and add in a "may become Animal Nemesis to some" at the bottom?