What IS this? Never encountered before

2 comments

1. That looks like herring with the roe still attached. Was it marinated/pickled? Pretty sure I’ve seen something like this on the sub waaaay back.

   Edit : Yup, found it : https://www.reddit.com/r/sushi/comments/pc08ti/trying_something_new_house_cured_herring_with_roe/

2. Are you in Vietnam? This is a popular item there. They make a version in red and one in green as well. Vinegar Cured Herring Roe.