Aquarium Power Outages – Simple Tips To Save Your Tank

There are two words which will send the majority of aquarium owners into a state of pure panic “Power Outage”.

To the owners who have prepared, the vast majority of power outages cause zero concern! Why? They have planned and tested their power backup systems! I almost learned the hard way and with my summers getting to +100°F and winters dropping to -35°F, I’m as prepared as I can be! Here is how you can get prepared too.

Dropping oxygen levels, changing water temperature and rising ammonia are all issues that will occur once the life support systems stop working on an aquarium. Battery backups, generators, stirring and heating water are short-term alternatives to ensuring livestock survival.

Protecting your aquarium from the loss of power can be dealt with by a few simple solutions or if mother nature decides to unleash her wrath you may have problems!

Read on to find out some great ways to help keep your tank alive…

How to Maintain Aquarium Health During a Power Outage

There are 3 categories to cover here:

  1. Free Ways To Help
  2. Cheaper & DIY Ways To Help
  3. Expensive Ways To Help

Free Solutions:

In addition to the solutions mentioned above here are a few more to try:

Stirring the Water

Using a large plastic serving spoon and manually stirring the aquarium water will ensure good gas exchange at the surface of the water and will keep the water oxygenated. It also helps to keep the temperature mixed throughout all levels in the aquarium and provide water movement for your corals.

You will get tired and needs stirring a few times each hour!

Jugging the Water

Similar to stirring but this involves using a measuring jug or cup and scooping up aquarium water and then pouring it back into the tank. This has the same benefits as stirring but will allow your water to cool. This could be a benefit if you are trying to reduce the temperature of your tank.

Cheaper & DIY Solutions:

The $3 Air Pump Using a Potato and Hydrogen Peroxide!

I’m not kidding! I was amazed when I first saw this! Check out his awesome video for a super simple way to keep your tank supplied with oxygen for hours!

NOTE that even though this produces the bubbles in the tank at a slow rate… we are adding PURE 100% oxygen. This is 5Xs more concentrated than regular air bubbles, so it doesn’t need to be a massive amount of bubbles. Keep this in mind.

Joey Mullen – King of DIY

Battery Powered Air Pumps

Manually Operated – This is a simple battery-powered air pump that you can turn on and drop the airstone into the water. However, this one requires you to install and operate but is a lifesaver for around $10. Check it out HERE at

Automatic Monitoring – This battery-operated air pump plugs into the wall to monitor the homes’ electricity supply. When the power goes out this pump automatically starts up and pumps air into your aquarium until the batteries go flat. A nice little set-and-forget unit for around $20. Check it out Here at

Be sure to have replacement batteries on hand to keep these pumps running!

These pumps are also very useful for transporting fish long distances!

Solar Powered Air Pumps

These little pumps are great to have on hand to work alongside the battery-powered air pumps. I would not rely on just one type as your batteries may go flat or it could be dark, but having both running and acting as a secondary oxygen supply to the other is good practice.
You can find a great kit Here at

DIY Battery Back-Up Systems

There are some awesome systems out there that can really help save your tank. If you are not practically minded or don’t have a DIY bone in your body I would stay away from these options.

Getting it wrong can seriously hurt you! I take no responsibility for your actions! There are numerous write-ups in the many forums on the systems fellow aquarists have designed and installed. There is also a good Wiki on DIY emergency power backup systems 😉

Solar Maintained System – This involves using a solar panel to charge and maintain an AGM battery or batteries linked in parallel to supply power to an inverter. The inverter will then supply power to your wavemakers, heater, chiller or lights.

Powering wavemakers and return pumps are the devices that are usually maintained, but items like heaters, chillers, and lights are power hogs and will quickly drain your batteries unless you have designed the system correctly.

Battery Maintainer System – This is identical to the system above except a battery charger/maintainer unit keeps the AGM battery maintained, rather than the solar panel.

Manufactured Battery Back-Up Systems:

There are 3 products I really like and depending on your equipment there is a solution to fit.

EcoTech Battery (Around $250 at – Designed purposely to be used with Ecotech’s range of wavemakers and DC return pumps.

Icecap Battery (Around $140 at – A backup battery that comes with a range of connectors to connect to many of the commercially available pumps and powerheads.

Tunze Safety Connector (Around $55 at – For use with Tunze’s range of controllable pumps and allows you to connect any sized 12vdc battery of your choice to power your Tunze powerheads.

UPS Battery Backup – Unfortunately I do not recommend these. They are designed to run for 10-20 minutes to allow a computer to shut down. They are constantly charging, which kills the batteries and therefore they only last a couple of years. They are also expensive!
There are far better solutions available for a lot less money.

For even more information on installing your own Battery Backup Systems be sure to check out my article:

Aquarium Battery Backups -Your Ultimate Guide

Expensive Solutions:

Portable Generators – There are some awesome generators out there to run your tank and having one that is fuel-efficient, quiet and easily maintained is a must.

There are two types of generators that I really recommend:

Gasoline Inverter Generators at – come in a range of sizes to meet your wattage demands and are inverter generators which in my opinion is needed with today’s digital electronics and controls. Some pumps can run backward when non-inverter generators are used!

Dual Fuel Inverter Generators at -These dual fuel generators can run on gasoline or propane and are my personal pick. Propane does not go bad like gasoline and having a 50/100lb tank sitting ready to go is great to have. Just like above, these are inverter generators that keep everything running good.

Here is my trusty steed, a Honda 1000i inverter generator and it has served me well! I’m getting the point where I need more wattage so ill definitely be looking to set up a dual fuel inverter generator with a 100lb propane tank and a transfer switch to ensure my aquarium is fully protected even when I’m not home.

Portable Generator Automatic Transfer SwitchThese great little devices I found at, allow you to have your aquarium circuits wired to this little device. You can plug the generator directly into it and providing your generator is of a big enough wattage, your entire aquarium system will be back up and running.
You will need a qualified electrician to do the work, but it’s a great way to ensure your entire aquarium system gets power.

Whole House Generator – These are by far the most expensive solution but are definitely worth thinking about if you can afford it. They are permanently installed on your property, run off propane and automatically detect a power outage and fire up to power your entire house.

Home Generator
Whole House Generator

They are a great option for peace of mind and you don’t have to be home to drag out the generator and fire it up to protect your aquarium.

These are going to cost anywhere from $8K to $20K depending on where you live and the size of the generator you require. Contact a local electrical contractor to find out more about them.

What Are Aquarium Concerns During A Power Outage?

The main cause of panic in new aquarium owners is “Oh my goodness my tank is going to freeze!!”, but the water temperature is #3 on the list of things you need to be aware of and pay attention to!

The three main aquarium considerations during a power outage are:

  1. Oxygen Depletion
  2. Ammonia Build-up
  3. Water Temperature


There are 4 main consumers of oxygen in your aquarium and they never stop sucking this stuff up! Fish, Plant Life (algae and plankton), Aerobic Bacteria & Micro-Fauna (Copepods, Amphipods, and Rotifers). – Links to my Abbreviations and Acronyms Page.

During normal, powered operation your water is being constantly replenished with fresh oxygen by the surface agitation of your aquarium water, water draining down into a sump and the protein skimmer to name a few. As water is moved it also releases the tiny amounts of nitrogen that is being produced as part of the constant Nitrogen Cycle.

If you want to find out more on the Nitrogen Cycle read my ‘How Do You Know When Your Fish Tank Is Cycled?’ article.

When your water stops moving due to the power outage, this renewal of oxygen is not taking place, but your aquarium inhabitants are still consuming. When your lights are also off the photosynthesis of the plant life reduces but this is only a small portion of the oxygen consumption.

The longer the power outage continues, the less oxygen will be available to keep the inhabitants alive. Oxygen depletion happens the fastest in most aquariums and should be the first item you need to address.

If you have a small nano-tank, temperature drop could be more of your first concern due to small water volumes losing their temperature quicker than larger volumes.


Just like oxygen, your living organisms are constantly going to the bathroom in the aquarium. Their excretions contain Ammonia or as their poop breaks down, will release Ammonia.

Your beneficial bacteria and filtration systems are normally doing their job to remove or convert the excretions and Ammonia. Once the power stops, the water is no longer being passed through the filtration media and your beneficial bacteria begin to die due to lack of oxygen.

The more bacteria that die, the less Ammonia is being processed which then accumulates in the water and eventually poisons your tanks’ inhabitants.

To learn more on how your bacteria convert Ammonia you can read my article on Fish Tank Cycling posted earlier.


I briefly mentioned in the Oxygen section that small tanks lose heat quicker than large tanks. This all comes down to thermodynamics.

Heat is a form of energy and how quickly your aquarium expels this energy to the surrounding air is called Heat Transfer.

Because water volume is cubed (in³, cm³) the amount of water that can store heat energy increases by a factor of 3 for each additional gallon.
Therefore the more water in your aquarium, the more heat energy your aquarium can store.

Small water volumes contain a low amount of heat energy.
Larger water volumes have a high amount of heat energy.

As your tank temperature cools, your living inhabitants begin to slow down, cool and eventually die. Depending on how big your tank is, depends on how soon this will happen.
Having a battery-powered digital thermometer like THIS ONE at is great for monitoring your water temp when you have your aquarium wrapped in blankets.

If you have corals, especially SPS your temperature drop will need to be far less to prevent them from dying, whereas most fish can withstand a larger temperature drop.

Anything below 76°F or 24°C you may start to see coral death
Anything below 70°F or 21°C you may start to see fish death

How Long Can An Aquarium Survive Without Power?

This is the ‘How long is a piece of string?’ analogy because there are so many factors affecting every aquarium. Some aquarium owners have seen death within a couple of hours and some people have managed to keep their tank alive for weeks following a hurricane/natural disaster.

Downed Power Lines
Downed Power Lines

The following factors influence how soon you could start losing fish:

  • Do you have a small aquarium?
  • Is your aquarium heavily stocked?
  • Extreme cold winter, house room temperature cools rapidly
  • Extreme hot summer, house room temperature warms rapidly
  • Has it been a long time since the last water change?
  • Did you heavily feed the tank just before the power outage?
  • Is the majority of your Live Rock stored in the sump?
  • Was there any fish illness in effect before losing power?
  • Were there any medications in use before losing power?

How Long Can A Coral Aquarium Last Without Power?

Corals are a little less forgiving when it comes to changes in the water parameters. SPS, especially Acros’ (Acropora), require the most stable water conditions whereas, Soft Corals like Mushrooms and Xenia can take a lot more fluctuation before they succumb. Again they could survive hours or weeks depending on how you are able to help them.

Corals will be affected by the conditions mentioned above as well as the reducing Oxygen, increasing Ammonia and the change in temperature but there are a couple of things you can do to help fend off the Grim Reaper:

  • Natural light from windows can help them coral photosynthesize. Use of a mirror to reflect light into the tank can help.
  • If you only have a small generator to power one or two devices at a time, rotate which devices run for 1 hour at a time. Lights then heater then wavemakers etc. Keep the cycle going so the corals get a bit of each device each day.

Will Aquarium Filter Bacteria Die During A Power Outage?

Yes, unfortunately. As soon as you lose power it won’t be long before your bacteria begin to die. How fast they die will depend on how many of your water parameters you can keep in the optimum range.
To view those optimum ranges check out my Parameters Guide.

As your bacteria begin to die the quicker your other parameters will begin to decline as mentioned in the Ammonia section.
The most important parameter to maintain for keeping your bacteria alive is Oxygen. Once this depletes, your bacteria will begin to die at a rapid rate.

Do You Feed Fish During A Power Outage?

Generally speaking NO, do not feed your fish. There are several reasons for this. Any food you feed and does not get eaten will settle in the tank and with a decline in your bacteria, there are fewer organisms to process it.

When animals eat, they go to the bathroom. Again, fewer bacteria means less processing, which means more toxic Ammonia.

The more your bacteria, fish and clean-up-crew work, the harder their metabolism works which mean they consume more oxygen. Can you see a pattern forming here?

As the temperature begins to fall your fish will eat less anyway. They are able to survive for weeks without food, so don’t worry about them going hungry!
Your corals will need some light though for them to survive long term. Look into getting them some natural light if you can.

Natural Sunlight on Aquarium

How To Prevent Aquarium Temperature Change During A Power Outage

Temperature is fairly easy to maintain but it requires constant attention and if you are away or are unable to ‘Baby-sit’ your aquarium then it may be more difficult.

Preventing Your Aquarium From Heating Up

This applies mainly to aquariums located in hot climates where summer temperatures get really hot. Many people will use the home air conditioner to help maintain temperature, but with no power = no AC!
Here are some ways to prevent your water from warming:

  • Ice placed in a clean Ziploc bags and floated in the aquarium
  • Wet towels wrapped around the aquarium
  • Opening windows in the home if there is a good breeze
  • Closing the curtains to keep out direct sunlight

Preventing Your Aquarium From Cooling Down

I live in a climate where our winters can drop to -40°C and this is the time that mother nature can wreak havoc with the power companies. Here are some tips to help prevent your aquarium from cooling too much:

  • Wrap your aquarium completely in Survival Blankets, duvets or whatever you can find. Leave a small opening at the top for gas exchange.
  • Warm water on a propane stove or BBQ to fill bottles and float in the aquarium
  • Keep the canopy closed as much as possible and resist repeated opening if you can
  • Light the wood-burning fireplace in the home if one is available
  • Keep the door closed to the room containing the aquarium

Planned Aquarium Power Outage vs Sudden Power Outages

A power outage is never a good thing but being prepared is the best thing you can do to save your aquarium. Sudden power outages usually cause the most stress as people are not ready for them. Here are a few tips you can to do be prepared for a sudden power outage:

  • Have your wavemakers and powerheads on battery backups so it’s not a big deal if you are at work or sleeping
  • Have the $3 air pump kits ready to go with a bottle of peroxide. Just add the potato
  • Have a battery-powered air pump installed or ready to install. Remove the batteries from the pump when not in use. Batteries leak! Have spare batteries
  • Purchase a solar-powered air pump kit like THIS at
  • Have a space blanket or two and some string in the stand to quickly wrap your tank
  • Have a couple of empty and sterilized 2L pop bottles ready to be filled with water
  • Ensure your BBQ propane tank is always full so you can boil warm water if you live in a cold climate
  • Keep your ice maker drawer full/buy ice bags if you live in a hot climate
  • Try and keep two storage bins of new salt mix and RO/DI water on hand at all times – This has saved me many a time, not just for power outages!
  • Have your generator serviced and ready to go. Have plenty of oil & propane/gas stored

Planned power outages or approaching storms can be a little easier to prepare for but you could be facing a long period without power so a plan may need to be drawn up.

As well as using the steps above you can also do the following items to help you prepare for the planned outage:

  • Reduce feeding your fish a week/few days before the outage to help reduce bio-load
  • Do a good water change the day of the outage
  • Give your tank a really good blast with the turkey baster and a good sand vacuum in the days leading up
  • Give all your pumps, heaters, lights a good clean/service to ensure maximum working efficiency
  • In the week leading up, try slowly increasing your water temperature a couple of degrees to buy more time
  • Drop some sponge filters into your sump to seed. You can then move them to the main tank to help the bacteria process waste

  • Stockpile all necessary supplies to last a week or even 2 weeks. Batteries, water, fuels etc
  • Get additional 12vdc AGM batteries and charge them if you have a DIY battery backup system
  • Get a solar-powered battery charger
  • Get a small 12vdc powerhead you can run directly off a solar panel. Ensure the pump is safe for saltwater!
  • Buy a service kit or 2 for your generator. You can run your generator for an hour, off for an hour to help prolong your fuel

  • Buy some Brute trashcans and stockpile water. Salt and fresh
  • Clean, sterilize and then fill your bathtub with RO/DI water
  • Ensure you have lots of salt stockpiled
  • Buy a few bottles of Prime water dechlorinator from
  • Have spare RO/DI filters
  • Get a mirror that you can use to reflect sunlight into your aquarium
  • Buy a Power Inverter like THIS at so you can hook up to your car to run some devices
  • Ensure your extension cords are long enough to reach the car/generator 😉
  • Ensure your cars’ gas tank is full. Buy additional gas
  • Stockpile wood or pellets to power indoor stoves/fireplaces

Short Power Outage Aquarium Preparation vs Extended Power Outage Preparation

Short term power outages are going to be more of an inconvenience to the aquarium owner. An all-nighter, a day off work or similar is just going to be frustrating but may need to be done to ensure the health of your aquatic family members.

Firepit Drinks
Get the BBQ/Firepit Tea & Coffee on the go!

Finding another aquarium owner who lives close by and befriending them is always a great idea. You can always be there to help each other out amongst the many other great advantages it brings. They may still have power and are free to just come over while you are at work and drop in your battery air pump etc.

Train your family members on how to do the basics like installing the air pump, blanketing the tank, etc so they can help if you are absent.

If you are facing a possible prolonged power outage you may need to ask for help with things like stirring and jugging your water. Tag team one another if it’s going to be a long journey. Get everyone involved and aware of what you may need help with on the days leading up to the planned outage.

Aquarium Tips After The Power Outage Is Over

You finally made it through and I hope you didn’t lose a single animal! But if you did now is the time to SLOWLY bring your aquarium back to full health. I know you have heard that saltwater aquariums do not like rapid changes and this process will be no different.

Here are some things you will need to be aware of and depending on how long your tank went without power and how off your parameters are will dictate how much of this you should follow.

  • Test all your water parameters to see where you are at and devise a plan to get them all back in line
  • You will have had a bacteria die off so your aquarium may have a mini cycle
  • Help increase bacteria by adding Dr Tims’s Live Nitrifying Bacteria or Prodibio Bio Digest ( Links)
  • Give your sand a good vacuum and your rocks a turkey basting to help remove detritus
  • Do several small water changes over the next few days to help to slowly reduce the ammonia, nitrates and dead organisms
  • Bring the temperature back up slowly. No more than 1 degree per day
  • Cut down your lighting period and intensity and slowly raise back to full operating settings over week/10 days to prevent bleaching
  • Unplug all your automatic dosers, feeders and ATO until you have your parameters plan in place
  • Monitor your city water for sediment and junk after a big storm. Replace RO/DI filters as needed
  • Slowly start feeding your fish. Do not overload what bacteria you have left
  • Service your generator and clean and replenish all your supplies. Fuel/oil/batteries/filters etc
  • Have your quarantine tank ready to go in case you need to remove and medicate a fish. ==>Read My Article On Quarantine Here<==
  • Don’t add any new fish or coral for a month. Let your bacteria regrow and stabilize

To Finish

As you have probably gathered the key to your aquarium surviving a power outage is to be prepared. There are many things you can do for free or relatively no money which is where you should start first.

The more things you can have prepared, the better your tank should survive and the less stressed you will be. Power outages can be a real nightmare to aquarium owners but having some kind of a plan will help you ensure no losses to your finned family members.

Now go and see how you can set up your own backup system!

Aquarium Battery Backups -Your Ultimate Guide

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Hi, I'm Richard and I have been an avid aquarist for over 30 years with a passion for Saltwater Aquariums. I love to pass on my knowledge to help others get the same amount a pleasure out of this hobby as I do. View my About Me page to find out more about me & my mixed reef aquarium.

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