system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: When a fish is pulled out of water does it die from too much oxygen?

I know this is really stupid but I can’t work this out in my head and google isn’t helping. From everything I can find it seems like a fish’s respiratory system works by filtering the needed oxygen out of the water through their gills.

So my thought is wouldn’t that just make breathing easier on land since they don’t have to do the filtering? I know this is a vast oversimplification but I can’t work it out. 

Does this mean that fish die from too much oxygen when on land? Or does their system just not work in regular air?

I guess TLDR: what exactly kills fish on land? Oxygen poisoning or suffocation?
gpt
Their gills are only able to respirate oxygen dissolved in water, they're not adapted for absorbing gaseous oxygen. It's the same reason we can breathe oxygen in the air just fine but can't do the same In water.