Sliver of salmon, tuna around some shoyu, slices of mackerel... (illustratively) (7)
I believe the answer is:
sashimi
But I can't explain it at all! Could you help me understand?
(Other definitions for sashimi that I've seen before include "Japanese raw fish dish - his aims (anag)" , "fish food?" , "Something of chef's" , "dish from Japan" , "Japanese dish of thinly sliced raw fish" .)