0303.42.00.20 - Whole fish

This HTS category, 0303.42.00.20, specifically covers whole yellowfin tunas (scientifically identified as *Thunnus albacares*) that have been frozen. This classification is reserved for the complete fish, in its entirety, before any processing that would separate the flesh from the bone or create fillets. The key defining characteristic is the genus and species of tuna, alongside its frozen state and whole form.

This category is distinct from its sibling, "Other," within the tuna classification. The "Other" category would encompass frozen whole tunas that are not yellowfin tuna, such as bigeye tuna (*Thunnus obesus*) or bluefin tuna (*Thunnus thynnus*), provided they meet the general criteria for heading 0303. The specificity of 0303.42.00.20 ensures accurate tariff application for yellowfin tuna.

As this is a leaf node in the HTS structure, there are no further subcategories. Therefore, classification to this level is final for whole, frozen yellowfin tunas. Importers and exporters should ensure that the product solely consists of whole yellowfin tuna, frozen, and does not include any other species of tuna or any processed forms of tuna meat or offal, which would be classified under different subheadings.