Is it possible to have too many plants?

[Ariel S]

Is “too many plants” a thing? 
 

I overheard a worker at my LFS tell another customer that having too many plants, but not running C02, can be detrimental to the fish because the plants will use up all of the oxygen when the lights are off. 
 

Any truth to that? Would they use enough oxygen to really affect the fish? 

[lefty o]

you would really have to have some major issues going on for even a crowded planted tank to potentially have something like that happen.

[CT_]

If you're worried an air stone would fix it, unless its floor to ceiling duckweed. 😅

[Pearl]

I've never heard of plants causing hypoxic conditions. They'll technically contribute at night, sure. But your going to need other factors, like some combination of high water temp, low circulation, terrible lighting, or lots of rotting detritus to be present for oxygen to be reduced enough to kill your animals I'd think. Co2 isn't going to help.