It's one thing if you make a youtube video starting from already knowing how to make modern fish sauces, and what they're supposed to taste like, and quite another level of horror if you don't. My recollection of the letter or paper or whatever it was was that the person who wrote it was not at all pleased with the result.

There are folks that will insist that we don't know at all what Roman garum really tasted like or everything involved in its preparation, and they're not exactly wrong since Colatura di Alici can only be traced back to the middle ages, but it's also oddly obtuse. I think it was probably like modern fish sauces but Roman garum could have been as different from Colatura and Asian fish sauce as those are from Worcestershire.