I really liked the film, in that schlocky, B-movie sort of way. The book, on the other hand, is forgettable. At a mere 143 pages, it darts along faster than the mutant piranha in the water, more or less rehashing the events of the book, though a few details are changed for some baffling reason. (Also, [MILD SPOILER] in the book, the fish get the dog. How many times do I have to say it: DON'T KILL THE #$%ING DOG!)
That it mind, the prose vacillates between cringe-worthy purple and slumber-inducing flat. The movie will definitely play a role in my research, and I suppose I'll take a snippet or two from the book as well. Nonetheless, I could have done without it.
It's out of print and hard to come by in the first place. (I snagged the last used copy available on Amazon.) Perhaps that's for the best. While I highly recommend the film, I can aver that reading the novelization adds no depth or further insight to the narrative.