One of fish keeping hobbyist's biggest nightmare- power outrage. What should you do and prepare for expected (known approaching hurricane or winter storm) and unexpected (thunderstorm, fire, flash flood, and other disaster) power outages.
An example of what power outrage can do to an aquarium is
New Orlean's Aquarium of the Americas' major disaster after 2005's
Hurricane Katrina. Just about everything that was not mammal or reptile perished during the disaster. The lone survivors were the mammals and turtles as they breath from the air.
Living in Wisconsin, the long, brutal winter can often cause power outrage during strong snow storms. And the threat is not only the immediate oxygen deprivation from uncirculated water, but the rapid temperature drop from the elements. For this reason, depends on where you live and what capacity your tank is, it is strongly recommended that you have a backup generator as your tanks' lifeline during times of emergency.
So the question is- how long can things survive without any back up? If the power outrage is temporary and will not last long during a relatively warm, summer day, no need to panic-
well, without flowing water to generate dissolved oxygen, most creatures will begin to display distress within a few hours depends on your bio-load. Imaging a fish can do alright in a bag of water during its transport from store to home (typically anywhere from 30 minutes up to 2 hours + acclimation time). That sac of water is definitely no more than 1/4 gallon. Now multiply that by how many gallons of water you have in your tank, and decided by how many fish/critters you have, you should get a pretty good rough idea of when your "deadline" is. That said, it's definitely not optimal to leave things as is. You can find
battery operated pumps in stores or online. Don't be cheap on this, it can save hundreds of dollars in livestock for you.
The bigger problem will present if the outrage is more than a few hours. While the back up battery operated air pumps can last a day or two, your water temperature will begin to decrease overtime, especially if you live in colder climate in winter. This is when you must invest in a
backup generator.
Once again, don't be cheap, this can save you hundreds, if not thousands of dollars of livestock. When choosing a back up generator, I would add up the wattage needed for heater and at least one powerhead for the fish tank portion of your household needs. corals and clams can survive a few days without light so light is not your priority for short term outrage.