How come fish can breathe under water, but are unable to inhale oxygen if theyre out of the water? If theyre able to filter it trough water, shouldnt they be able to use it directly?

Question

How come fish can breathe under water, but are unable to inhale oxygen if theyre out of the water? If theyre able to filter it trough water, shouldnt they be able to use it directly?

In: Biology

Answer 1

Their gills are relatively fine and collapse when out of the water. It’s not usable when it collapses like that.