To help them breath!
The gill rakers on fish keep food particles from moving out from in between the gill arches. For filter feeding fish and some suspension feeding fish, the gill rakers function is to trap the food.
It is used to cover the gill on the fish.
a gill cover is used to cover the gill on the fish
the gill operculum covers and protects the gills.
gill is a part of a fish.
The flap of tissue that covers a bony fish gill is the bony operculum.
gill slits
A fish breathes through its gills.
Gill.
The black and white fish Named "Gill" from Disney/Pixar's Finding Nemo is a Moorish Idol. Though aquariums often state this fish as a Black and White Heniochas.
Fish open and close their mouths to breathe, eat, and communicate. Gill slits are openings on the sides of the fish's head that enable water to pass over the gills, where oxygen is absorbed and carbon dioxide is released. This process is essential for respiration in fish, allowing them to extract oxygen from water to survive.
gill