How can you have water with no oxygen

I have my pharmasist this question too she didn't know either. I have watched numerous deep water exploration shows where they talked about water that was so deep that there was no oxygen...water is H2O so how can you have water with no ox ?

You always have the O in H2O. The show was referring to gasseous O2 that is dissolved in water. This is what fish "breathe" with their gills.

If put a fish into pure H2O with no gasseous oxygen dissolved in it, the fish will quickly die.

Water isn't Oxygen. It just has Oxygen bonded. Bonded Oxygen isn't breathable Oxygen. We breathe Oxygen molecules, not Oxygen anions.

It can contain only H2O molecules and no O2.