Power failure and my fish tank

My recent experience:
We had a 36 hour outage two weeks ago, and my generator didn't/wouldn't start. As I have around 6000l across 5 tanks, there is little you can do about temperature or filtration. All I did was add battery operated pumps, aside from my large tank where I lost 4 large tinfoils, probably due to stress as these are easily stressed fish, all other fish were ok including rays and Asian arowana.
Large tanks loose temp very gradually, and most tropical fish will die when temps reach around 12 degrees. The power came back on at 1:00am whilst I was sleeping none of my filters seemed to have crashed, I have mostly canisters, sump, and in-tank filters.
I tested my water parameters the next morning, all were ok, nitrates were somewhat elevated, did 50% water changes, no further issues.
My previous "record" was 18 hours.
The most important step to take is to provide oxygen by agitation of the water via air pumps.
As the temperature drops the metabolism of fish slows, they use less oxygen, and cooler water can carry more oxygen.
I won't say I wasn't stressed.

 

Yew @Jwh.... that was a hell of a long time.. I am sure your stress levels must have been hitting the roof!!!

Glad you pulled it through with minimal losses.. i would have thought it would have been worse...
I agree that the big tanks loose temperature slower than small tanks which helps a lot

As for oxygen although we have also bought a generator, i still have some battery operated air pumps and some AC/DC pumps which kick in when the power goes off when we not home and tey last quite a few hours
They are worth every cent

 

Thanks all for the replies. I managed to make it through the 8 hour outage with no lives lost. I hooked up 2 2000VU UPS's to my 2 biggest tanks and ran the air pumps and filters via the UPS's. I left the heaters off as they draw the most power. All in all pretty impressed with the up time I got from these 2 UPS's as they lasted the 8 hours and only lost about 35 - 40% battery power. So I can now sleep a little bit better knowing the fish are talent care of when Eskom fails them. The tank temps remained quite high, only dropping 5 degrees in the 8 hours. Bearing in mind that it lasted throughout the entire winterish night without any heat introduced to the tank. So all in all I can sleep peacefully now.

These are the UPS's for anyone interested.

https://www.takealot.com/mecer-2000vu-line-interactive-ups/PLID34152441