What is a crucial identifying mark often found on the gill plate of *O. niloticus*?

Answer

A distinct dark spot on the operculum

A key identifying mark for distinguishing Nile tilapia from other related species is the presence of a distinct dark spot on the operculum, which is the bony flap covering the gills.

What is a crucial identifying mark often found on the gill plate of *O. niloticus*?
sizefishbodycharacteristictilapia