YEP, this works with luderick but you can also use other types of fillet.
The person who showed be was Japanese so here goes (vaarree eeessiee):
1) Get some fresh fillets of luderick (or another species of you want)
2) Cut the meat up into thinnish slices or small chunks
3) Get an average size bowl and fill it 2/3 full with white vinegar
4) Chuck in a generous sprinkle of mixed herbs
5) Cut an onion into thin slices and chuck that in too
6) Stir it a bit then submerse the luderick slices in the concoction
7) Put it in the fridge and leave for 24 hours (or at least overnight)
8) Use a fork to extract the fish slices (as you need them) and eat at your leisure
9) It'll be ok to leave in the fridge for a few days to pick on at will
10) I tried it a few times and it works...too easy lemon squeezy!