Certain fish have special organs that generate an electric field around their body called an electrosense to help them locate food and communicate.
Fish extract oxygen from the water. How quickly they breathe depends on the temperature of water, level of oxygen and how fast they are moving.
Fish will often cough to dislodge particles trapped in their gills. Fish use gills, not lungs, to extract oxygen. When a fish breathes, the gill cavity expands and water flows in through its open mouth. The mouth
is closed, gill cavity contracted and water pumped out over the gills.
The exchange of oxygen and carbon dioxide takes place as the water passes over the gills.
In the deep sea where there is low dissolved oxygen, some fishes can fabricate a store for themselves and keep oxygen in their
There are even fishes that breathe atmospheric air. These are the
Labyrinth fishes. These fishes have an extra respiratory organ which
is situated in each gill cavity. These organs supplement the gills in
water with low dissolved oxygen.