0303.39.01.20 - Rock sole (Pleuronectes bilineatus)

This classification covers frozen rock sole (scientific name: Pleuronectes bilineatus) that are not fillets or other fish meat of heading 0304. Rock sole are a type of flatfish belonging to the Pleuronectidae family, distinguished by their asymmetrical body shape and often found inhabiting sandy or muddy bottoms. This category specifically isolates rock sole from other flatfish species for import and export purposes.

The key distinction of this sub-subheading from its siblings lies in the specific species identification. While sibling category 0303.39.01.10 encompasses various types of flounder, and 0303.39.01.30 specifically identifies yellowfin sole, this heading is exclusively for rock sole. The residual category 0303.39.01.95 serves as a catch-all for other flatfish not otherwise specified.

As this is a leaf node, there are no further subcategories. The classification of frozen flatfish ends at this specific level of species identification within the "Other" category for flatfish. Therefore, proper identification of the species is paramount to ensure accurate classification under the Harmonized Tariff Schedule.