Why is a power loss THAT bad?

[ScubaSkeets]

Hi folks!
Luckily for me and knock on wood, it hasn't happened to me. However, I've seen/read stories of people losing fish due to power losses. With the exception of the tank getting too cold or too hot, what are the dangers of losing flow/circulation for say, a day?
Oxygenation? Aren't fish in sealed bags for shipping? Can't fish survive in (temporary) stagnant water? Can't they survive in temporary colder or hotter water? What else is there?
If I'm incorrect and a power loss for more than an hour or two is more dangerous than I thought, is having a circulation pump on battery back up what's needed most?

 

[Rmckoy]

Circulation and gas exchange
Oxygenation , photosynthesis ,
More than as simple as fish being stuck in shipping bags for a
Few hours .

 

[Rmckoy]

During the the Texas power outage . There was a write up about power outages , I can’t remember who wrote it ...... but was a lot of helpful information

 

[PeterC99]

Correct about “temporary” power loses and minimal impact to aquariums.

The problem is the unknown duration of “temporary”!

 

[fish farmer]

Correct about “temporary” power loses and minimal impact to aquariums.

The problem is the unknown duration of “temporary”!

Exactly.

It is all about biomass. How heavy is your fish/coral load? I've had about a hour or two outtages on my current tank with no problems and longer when I didn't have as much stock to lose and it was fine.

 

[PeterC99]

Exactly.

It is all about biomass. How heavy is your fish/coral load? I've had about a hour or two outtages on my current tank with no problems and longer when I didn't have as much stock to lose and it was fine.

Great point!