Of all of the many and varied animal-attack films that followed in the wake of Jaws (1975), Joe Dante’s charmingly daft Piranha is by far and away one of the best, though given the state of so many of the others, that might feel like damning with faint praise. Prior to Piranha, Dante had only co-directed Hollywood Boulevard (1976) with Allan Arkush (The Movie Orgy from 1968 had been more on an editing job than a directing gig) and here his tendency to overload the film with in-jokes and cameos from Hollywood stars of old is tempered by a genuinely witty script, his first, by John Sayles.

Piranha opens, as did Jaws, with a nocturnal attack by something lurking just below the water’s surface. In this case, the water is a pool in a seemingly abandoned military base in the hills of Texas near Lost River Lake and the first victims are a skinny-dipping couple. Scatterbrained but enthusiastic skip tracer Maggie McKeown (Heather Menzies), who claims to be “two thirds bloodhound”, is sent to find the missing teenagers, teaming up with surly alcoholic Paul Grogan (Bradford Dillman) who reluctantly agrees to be her guide. They find their way to the base where they fail to spot a nicely animated little mutant creature but do find a skeleton in the pool’s filtration trap a panicked scientist, Dr Robert Hoak (Kevin McCarthy). He reveals that the pool was, until recently, full of genetically mutated and highly aggressive piranha, specially bred for combat duties in the cold waters of North Vietnam and that they’ve recently escaped into the nearby river. McKeown and Grogan are sceptical until they find the mutilated remains of Grogan’s friend Jack (Keenan Wynn). The race is now on to alert the authorities and prevent the fish from attacking the celebrations for the opening of a new dam, with Colonel Waxman (Bruce Gordon) and former Operation: Razorteeth scientist Dr Mengers (Barbara Steele) both helping and hindering along the way.

Piranha was an early outing for most of what would become Dante’s stock acting company – Paul Bartel is a riot as a sadistic camp counsellor and Belinda Balaski gets a small role as one of his employees. The rest of the cast are well stocked with the 50s and 60s genre icons that Dante would often found work for over the coming years, Dick Miller joining Wynn, Steele (whose chilling “there’s nothing left to fear” at the climax doesn’t really inspire much confidence) and McCarthy. Menzies and Dillman are great as the mismatched leads, her sparky enthusiasm contrasting nicely with his world-weary cynicism and the relationship between them is pleasingly fleshed out by both Sayles and the two actors.

Sayles is probably the film’s most valuable asset, his script dripping with darkly witty asides (“the piranhas… they’re eating the guests, sir”) and neat twists to a formula that had yet to be set in stone – most of the eco-horrors of the 1970s adopted a “green” approach, a plea for better treatment of the environment and its wildlife. Grogan is more gung-ho and less cautious, happy enough to kill the piranha shoal by deliberately releasing industrial waste into the picturesque lake: “we’ll pollute the bastards to death!”

Thanks to the strengths of Sayles’ script, Dante gets the right balance here between the in-jokes (a girl on the beach reads Moby Dick, McKeown plays a Jaws computer game and The Monster That Challenged the World (1957) is playing on television) and the horror, something he wasn’t always able to do in later films, and there are some moments of real tension here. He’s smart enough to realise that he’s making a knock-off exploitation film (Roger Corman was the executive producer after all) and doesn’t skimp on all the elements we expect, particularly the gore (special make-up courtesy of Rob Bottin and Vincent Prentice). But Sayle’s script is a cut above – witty, exciting, even quietly moving at times. It’s a little rough around the edges at times but that only adds to the film’s many pleasures and it’s energy, witty dialogue, satirical barbs (there’s something immensely pleasing about seeing the vile, self-serving Waxman meeting a sticky end) and unashamed exploitation elements are simply infectious.

Piranha is hugely entertaining, more fun than you might expect from what was supposed to be just a quick cash-on and unexpected flourishes like that never-explained stop-motion mutant (designed and animated by Phil Tippett) are essentially unnecessary but still very welcome. The piranha themselves are mostly kept out of sight, just glimpsed as a flurry of fins and teeth (we get a better look at the Robert Short and Chris Walas’ props in the stills) but their presence, signalled by a creepy sound that one assumes is the chattering of their flesh-ripping teeth, is nonetheless an unnerving one. Balaski being dragged to her doom towards the bottom of the lake in a cloud of her own blood is a particularly memorable image.

Sayles’ script skates close enough to the Jaws template for Universal to have considered trying to block its release in 1978, the year they had Jaws 2 ready for release, but Jaws director Steven Spielberg was so impressed by Dante’s work that he made favourable comments (he’s called it “the best of the Jaws rip-offs”) about the film and Universal relented. Dante and Spielberg would work together many times over the coming years with Spielberg producing Dante’s Gremlins (1984), episodes of Amazing Stories (1985-1987) and Innerspace (1987 among others and the two worked together with John Landis and George Miller on the ill-fated Twilight Zone: The Movie (1983).

Piranha remains one of Dante’s best films and has been popular enough to warrant a hilariously awful in-name-only sequel, Piranha II: Flying Killers (1981) – directed by none other than James Cameron, though he rarely admits it these days – and two remakes, Piranha (1995) and Piranha 3D (2010), the latter getting a sequel of its own, Piranha 3DD (2012). It scarcely needs saying that none of them are a patch on the original and indeed Dante was never going to quite scale its heights again.