Flounder / Halibut (fresh)

Although plaice and halibut are not listed under their specific species names on the basic SIGHI list, they fall under the general category of freshly caught or deeply frozen fish, which are classified as a 0. These white marine fish are characterized by a lower natural content of the amino acid histidine and are usually better tolerated by individuals with histamine intolerance than fatty fish, but their tolerance is—just like for the entire category—extremely dependent on immediate freshness and species. Despite a more favorable initial profile, they are subject to rapid microbial decomposition, and therefore it is imperative to consume them exclusively at maximum possible freshness or deeply frozen, as purchased chilled fish (category 3) experience a very rapid accumulation of histamine.