The risk is that it gives the edited catfish a survival advantage over wild-type catfish which could result in extinction pressures on the unedited fish. This would not be a problem if the species could interbreed and spread the advantage across all subspecies.
The problem with the story is that they emphasized the “aligator DNA” to drum up excitement and create sci-fi buzz. If they had just published the actual gene sequence and called it “kitten DNA” or “cuddly puppy DNA” nobody would click on their post.
The “Jurassic Park’ franchise scenario has been repeatedly declared impossible by so many scientist and yet they seem to be doing their best to prove themselves WRONG!