Joe Dante's Piranha is the notorious 1978 Jaws rip-off from Roger Corman, with piranhas rather than sharks. Reasonably gory but great fun. Barbara Steele is delightfully evil. I often enjoy rip-off movies more than the movies they ripped off.
My review: https://princeplanetmovies.blogspot.com/2023/06/piranha-1978.html
@d4doome the only film I have ever walked out of. I was 12 and for some reason it was shown at a kids film show in local church hall instead of the advertised King Kong.