Let's get the bad stuff out of the way first. Frankenfish (2004) is a typical B-movie horror/comedy flick about genetically engineered fish who get loose and run amuck, killing everything in site. It's dumb, lame, and also a lot of fun.
When people start showing up dead in the Louisiana swamps, apparently eaten by something, a medical examiner and a wildlife expert are sent in to figure it out. It turns out the fish are a mutant type of Chinese Snakeheads, known to be vicious and able to leap onto land and live for extended periods.
The two experts team with locals living in the swamp to try and deal with the fish, but things go badly and people turn into fish food at an alarming rate. One line from the movie kind of says it all: "You look great for a girl covered in giant fish brains." Youbetcha.
Naturally, to make this a complete B-movie, the producers were kind enough to throw in some gratuitous nudity which was totally superfluous to the story, out of context, and made no sense, but hey, the boobs were big. A great choice for an evening when you're looking for a fun, no-brainer monster flick.