noun
flathead silverside
A species of silverside fish (Hypoatherina valenciennei) found in coastal waters of the western Pacific. The name is usually written in katakana.
トウゴロウイワシは沿岸の浅い海でよく見られる。
Flathead silversides are often seen in shallow coastal waters.
The name likely derives from a combination of a personal name (藤五郎 or 頭五郎) and 鰯 (iwashi, 'sardine'), but the exact origin is uncertain.