Here in the province, rotating brown-out is still experienced by every electric consumers. Aside from the home appliances that will sure to get affected from the abrupt change of the electric current, our fishes in the aquariums are also affected as their air pump is stopped.
Image is not mine
During the last black out here in the area, I just found one dc12v power supply which is supposed to be for keyboards. But I tried it for aquarium air pumps, and good to see that it was working. At least the fishes has air supplies then.