Fish Question???

Question

If fish breathe oxygen underwater, why can't they breathe out of water where there is plenty of oxygen???

Answer 1

Cuz water is made of Hydrogen and Oxygen. The air you breath has other gasses in it, Nitrogen, Helium, Pollution, etc... Same question could be asked of you, you can breath the oxygen out of the air, why can't you breathe it out of the water? The main problem lies with the amount of oxygen available and how it is being absorbed by the body.

Answer 2

They can't breathe straight oxygen; they are built to bring in water and extract the oxygen from it not, they don't "breathe" oxygen they breathe water and get oxygen from it.

Answer 3

here you go.

http://www.straightdope.com/mailbag/mfishbreath.html

i was curious about it too one day.

however there are certain speceis of fish that can survive out of water. i have a rope fish that has a modified swimbladder that is used to essentially breath oxygen. he can survive out of water for roughly 2-4 hours before he would dry up. also look into the birchirs. i have a nigerian senegalus (Nigerian Birchir) that has a special protein coating on his scales that prevents them from drying, he also has a modified swim bladdar and can breath air. he has the ability to stay out of the water for 1-2 days. the reason for this is because in his natural enviroment, the streams and puddles are very muddy and dont have much oxygen so he has to beable to breath air as well as water to survive. also during the dry season, he is able to go from puddle to puddle to survive.