noun
gill cover; operculum
Anatomical term for the bony flap covering and protecting the gills of fish.
魚のえら蓋が開いていると、新鮮ではない可能性がある。
If a fish's gill cover is open, it may not be fresh.
解剖図でえら蓋の位置を確認した。
I checked the position of the operculum on the anatomical diagram.
Katakana-hybrid spelling sometimes seen in informal or technical writing.
Full katakana spelling; may appear in biological contexts or emphasis.
えら refers to the gills themselves, while えら蓋 is specifically the protective cover over the gills.
Compound of えら (gills) and 蓋 (lid, cover). The kanji 鰓 is a specialized character for gills, but the mixed kana-kanji spelling is more common.