Some info on German torpedoes
https://uboat.net/technical/torpedoes.htm
there is much more you can find on them on the web, including the link at the top of that page. The Japanese destroyed a lot of information as the war came to a close, so we rely upon information gleaned from interviews and books. They may have been working on a acoustic torpedo, but I've not seen info. They did however, have
the kaiten which had minor success (I wouldn't want it to be considered 'minor' if they hit my ship), but most Japanese crew reports from the field were often over-exaggerated, such as their attack on Ulithi Atoll.