don't you mean: what does the gill arch do in a fish?!
To incease the surface area of the gills so more oxygen can be diffused from the water the fish swims in into there bloodstream where the oxygen can be carried the fish's cells for cellular respiration
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
gill is a part of a fish.
the gill operculum covers and protects the gills.
The flap of tissue that covers a bony fish gill is the bony operculum.
gill slits
Gill.
A fish breathes through its gills.
gill slits