How does a fish operate? · Respiratory

Fish extract oxygen from the water (breathing / respiratory actions). Pumping water in from their mouths and over their gills. However, sharks and rays have spiracles, auxiliary water intakes near their eyes, for this function.

Fish suffocate when water flow is stopped or interrupted, caused by mouth and nose trapped shut, fish being dragged backwards, facing a fish downstream to the tidal stream.

How sensitive is a fish?