lt. claude ( claudio cassinelli ) and several prisoner from his sunken ship wash ashore on an island own by edmond rackham ( richard johnson ) . follow a few random prisoner death and rackham take in claude and his two remain prisoner . luckily for everyone and barbara bach just happen to be on the island too . unluckily and there be some crazy fishmen who like to kill people . this italian produce exploiter seem to have it all a touch of creature from the black lagoon mixed with dr. moreau with a dash of white zombie voodoo and atlantis stuff . despite some wonky look fishmen costume and the film do benefit from some beautiful location photography and a nice twist about halfway through . all of the actor be good and joseph cotton even pop up a a old biologist . director sergio martino handle himself well enough a there be action ever 10 minute or so . that can not be say for his belated follow up the fishmen and their queen ( 1995 ) and easily one of the wacky and most off base sequel since highlander ii .