Changes which occur during a power outage (continued)
Change in temperature
After oxygen depletion, temperature fluctuations are the next most dangerous change in a power outage. Most well-insulated homes will maintain their temperature for several hours. Try to keep the temperature in the room as steady as possible. In cold weather, building a fire in the fireplace or draping a blanket over the tank to help insulate it may help. In severe cases, adding hot water or ice to the tank may be tried but realize that in a large tank, the amount of hot water or ice that will need to be added to significantly alter the temperature may be unreasonably large. Also, the sudden change in temperature as you add the water/ice, even if it is only several degrees, may be more stressful for the fish than the gradual temperature change due to the outage. Long power outages in very hot weather can be particularly deadly to a reef tank if the owner does not have a generator.
Once the power comes back on
When power is restored, be aware that the biological waste present in the tank and mechanical filtration pads may have started to be broken down anaerobically producing methane and hydrogen sulfide. These gasses can be very toxic to fish, so try to remove and clean the filter pads before the power comes back on. If the power outage lasted more than several hours, realize that your fish will be very stressed. Monitor them closely while disturbing them as little as possible for the first few days. If you see signs of ich or other diseases developing, take appropriate treatment action. Monitor the water quality as well and do not be afraid to do water changes to help get the water quality back to normal.
While a power outage can be a disaster for aquarium owners, it does not have to be. By taking a few precautions and buying some basic emergency equipment, you can protect your tank from the potential dangers of your next power outage.
