Severe Storm Informaton


First and foremost make sure you and your family are prepared and safe before worrying about your fish!

Before the storm arrives there are things you can do to prepare and increase the survivability of your aquatic creatures.

  1. Cut back on your feeding – less waste means less oxygen demand (amount of oxygen being used by the aquarium ecosystem)
  2. Stop feeding ~24 hours prior to the storm arrival – this allows the fish to fully digest what is in their system prior to the power outage and reduces oxygen demand by bacteria.
  3. Do a partial water change 36-48 hours prior to the storm – clean out as much debris as possible to reduce oxygen demand. This includes changing replaceable filter pads.
  4. Common questions we are asked about Computer UPS backup systems, battery operated pumps, and generators.
    1. Computer UPS (uninterrupted power supply) systems typically will only keep THE ENTIRE aquarium running for 20 minutes up to a couple hours. The power drain from your main pumps is very similar to the power drain of a computer that is being used (not sitting idle).  This system is usable for short duration, but is really impractical if we are expecting a major storm and you want to run the whole filter system.
    2. A UPS WILL RUN A SMALL CIRCULATION PUMP or AIR PUMP FOR MANY MANY HOURS, EVEN DAYS if done properly use a small low watt air pump or circulation pump (1.5 – 3 watts is all that is needed).  Circulation pumps should be directed at the surface of the water (to keep the surface agitated and re-oxygenated constantly).   This method works great!
    3. Battery operated air pumps are useful, but the batteries will not last long (typically 6-8 hours max.).
    4. Generators can be used, but only if you have a very good surge suppressor in line with your pump. Most of the pumps we use are electromagnetic actuated mechanisms.  That means the power is transferred through an electromagnet to turn impellers or to move a diaphragm.  Electromagnets depend on very clean stable electricity, something very few generators produce (unless the generator incorporates electronics to smooth the power).  The best solution if you have a generator is to put a good surge suppressor (computer type) in line between the generator and the aquarium.  If you have a generator make sure you test your aquarium pumps prior to the power failure to make sure it will work.  From personal experience, we can tell you that it sometimes takes more than one surge suppressor to clean up the power from a generator before it is usable. Modern whole home generators and many portable generators typically have these surge suppressors built in, but test it to make sure.
  5. Make sure you and your families are also prepared


If and/or when the power fails – Remember its all about the dissolved oxygen in the water


  1. Leave the fish alone! The more you disturb your animals the more oxygen they will use.
  2. Keep the aquarium dark. The power is out so you don’t need to turn the light off, but if the aquarium is in a room with a lot of natural light from windows, cover the aquarium with a dark sheet or blanket to block out the light.  If the fish (and inverts) are in the dark, they will rest and use less oxygen.
  3. THE POWER HAS FAILED — WHAT CAN YOU DO? Most aquariums will be fine for ~24 (depending on oxygen load) hours if the fish are left alone in the dark.  The following are steps to take to ensure the survival of your critters.
    1. Leave the fish alone; cover them to make the tank dark.
    2. Heat is a big concern in our area.
    3. Ice will have little to no effect on the temperature, it will only cause stress by bouncing the temperatures for the animals.
    4. If the animals are in the dark heat will have less of an effect on the overall system. The key is to keep the animals in a reduced respiration state (dark and quiet) so that their systems can temporarily combat the heat.
    5. Wrapping an aquarium (blankets, insulation, etc) can help temporarily, but the thermal loads will overcome most insulating wrapping in several hours.
  4. Check the animals every 4-8 hours and observe the inhabitants for signs of oxygen distress.
    1. Oxygen distress is shown by the fish when they start to hover near the surface with their mouths right near the surface of the water – they are trying to get oxygen from the surface film (where oxygen is diffusing into the aquarium).
    2. Be very quite when observing the fish – you do not want to raise their metabolism, or scare them to where you cannot observe the oxygen distress behavior.
    3. If you observe oxygen distress behavior, you need to re-oxygenate the aquarium using the water dumping method.  Stirring the aquarium with a giant spoon will do nothing but excite the fish and increase oxygen demand.
      1. Open the top of the aquarium and/or remove the glass tops.
      2. Take a pitcher or sizable container (make sure it is clean), scoop up some aquarium water and poor it back into the aquarium from a height of 1-2.5 feet. This will disrupt the surface helping to re-oxygenate the water, while mixing the tank thoroughly.  Repeat this continually for about five minutes. This should bring the aquarium back to near the oxygen saturation point.
  • Check the fish every few hours to see if you need to repeat the re-oxygenation procedure.
  1. Over time you may find that the periods between the need to re-oxygenate the aquarium start to decrease (get shorter between signs of distress). This indicates that the oxygen demand (amount of oxygen being used) is increasing due to increased animal or bacterial respiration.
  1. What do you do if re-oxygenating becomes to frequent or simply cannot be preformed (have to leave)?
    1. You can use hydrogen peroxide to re-oxygenate an aquarium – This is a risky procedure and should only be done if absolutely necessary!!! Use the water dumping method first!!
    2. You need to know the volume of your aquarium, and the approximate displacement by decorations, rocks, etc. IT IS CRITICAL THAT YOU DO NOT OVERDOSE THE AQUARIUM!! If you overdose the aquarium, the oxygen levels will skyrocket past saturation (super saturation) and possible kill if not seriously harm your fish and inverts.  Corals and anemones are especially sensitive to super saturation.  Overdosing can lead to gas bubble disease and oxidation of gill, fin, and skin tissues (similar in effect to an acid or alkali burn on humans – not cool).
  • If you haven’t gotten the hint yet; DO NOT DO THIS EXCEPT AS A LAST RESORT!!! That means you are actually in the process of loosing animals, or the loss of animals is emanate.  This is not something to fool around with, improper use or overdosing will kill animals, coral, anemones, bacteria, and anything else living in the aquarium.

**** –  Aquarium World does not make it a practice of providing this information, as every aquarium is unique, and dosages can vary.  In light of the possible hurricane strike we thought it best to give our customers the tools necessary to survive an extended power outage.  We are not responsible in any way for any loss incurred by using the following dosages as we do not know the actual loads or oxygen demand on your system.  End of CYA statement — folks; please be very careful doing this and start with low dosages before attempting a full dosage.

Proper dosage is 1 teaspoon of standard grocery/pharmacy grade hydrogen peroxide per each ten physical gallons of water in a properly maintained low oxygen demand system.  There are technical ways to measure the oxygen demand, but they are beyond the abilities of almost all aquarists (requires lab equipment). WHAT THIS MEANS BEFORE YOU START DOSING

    1. Big Freshwater :  If you have a 75 gallon aquarium (only really hold ~72 gallons of water) with 25 approx 3” African Cichlids and you do regular water changes (monthly) and only feed what the fish need, you would most likely have a low to moderate oxygen demand.  You put ~75 lbs of gravel in the aquarium and 50 pound of rock and décor, so you probably displaced 5-10 more gallons of water.  This means you are dosing for a maximum of 62 gallons – always error on the conservative side and overestimate displacement!!.
    2. Small Freshwater : If you have a 15 gallon aquarium (only really hold ~13 gallons of water) with 15 approx 1” Community fish and you do regular water changes (monthly) and only feed what the fish need, you would most likely have a low to moderate oxygen demand.  You put ~15 lbs of gravel in the aquarium and 10 pound of rock and décor, so you probably displaced 2-3 more gallons of water.  This means you are dosing for a maximum of 10 gallons – always error on the conservative side!!.
    3. Saltwater: Saltwater holds less oxygen so you are working at a deficit to start with. Look at your total tank volume do not include sumps as they are not working during a power failure.  In reef and Fish tanks you will have to do a best guess on the amount of water your liverock and décor displaced – it is better to over estimate displacement (this will lower the total dose) – be careful!  Dosage is the same 1 teaspoon per 10 gallons in a well maintained aquarium.
  • It is very difficult to estimate the oxygen demand for your aquarium, so error on the safe side and START WITH A HALF DOSAGE in a well maintained aquarium. START WITH A QUARTER DOSAGE in an aquarium that has not been properly maintained.
  • TO DOSE THE AQUARIUM use regular hydrogen peroxide from the grocery or pharmacy (you may have this in your medical supplies already).  You will have to best guess your dosage based on tank volume on oxygen demand. We recommend starting with 1/4-1/2 dosage (1 teaspoon per 40 gallons= ¼ dose), then increase the dose if necessary by stepping up the dosage over treatments.  Do not start with a full dose unless you really know what you are doing!
      1. Start by aerating the aquarium using the water dump method for a minute to two minutes.
      2. Add your hydrogen peroxide to a pitcher full of water. Dump the mixture from 2-3 feet above the aquarium as you were doing before
  • Continue dump aerating for two more minutes to completely mix the oxygenated water throughout the aquarium. You do not want pockets of supersaturated water.
  1. If you are dosing properly you should get oxygen saturation and won’t need to re-dose or water dump aerate for ~12 hours.
  2. IF YOU OVERDOSE: The animals will start to dart about due to supersaturated oxygen levels – IMMEDIATELY AERATE USING THE WATER DUMP METHOD UNTIL THE ANIMALS  STOP SHOWING DISTRESS.
  3. If you started with a reduced dosage and notice that the animals show signs of oxygen depletion within a few hours, increase the next dosage by about 10%.  Step the dosages up this way until you find a comfortable stable dose.




  1. CANISTER FILTERS: What to do before the power comes back on if you have a canister filter.
    1. If you have a canister filter, you need to empty it if the power is off for more than 24 hours.
    2. Water will become anoxic (no oxygen) in a sealed canister resulting in hydrogen sulfide and other pollutant buildups. When the power comes on these products of an oxygen starved environment will be pumped into the aquarium and potentially kill your animals.
    3. Empty and rinse (as best as possible) any Canister filter that has been down for more than 24 hours.
    4. Other sealed filters should be treated the same as canister filters.
    1. Make sure your filters are working
    2. Remove any inhabitants that might not have survived
    3. Test your water primarily for Ammonia and Nitrite
    4. Perform a partial water change if the test results indicate the need.
    5. Do not over react!! If you are simply reading trace amounts of ammonia or nitrite do not panic!  Wait a day and test again.
    6. Overreaction can cause more harm – Let your aquarium stabilize
  3. Your aquariums Ecosystem has just gone through a major stress, give it time to stabilize naturally if possible. If you overreact and start treating with a lot of chemicals you can very easily destabilize the environment even more.  BE PATIENT.