Fish Room Emergency

Just when you think you’ve got it all under control…

The sidewalk’s shoveled, parking spaces are plowed, door locks are thawed, and the chatter of a store full of customers is drowning out the incessant but disregarded humming, whirring and bubbling sounds of tanks full of happy, healthy fish.. Then, instantaneously and without warning, the whole scene is plunged into an eerie darkness and silence.

A loss of electrical power is a nuisance for people: we might miss a rerun of “Crocodile Hunter” or a Rush Limbaugh monologue, or the toaster pastries might never get done. But for a tank full of fish, an outage means their life support systems are no longer functioning, and catastrophe is right around the corner. And while a few of the best-prepared shopkeepers and managers will not only possess but know how to use a gas-powered generator, most of us will just tough it out and hope for the best.

The first rule in any emergency is to step back and take a moment to assess the situation before making a first move. Many situations are not nearly as dire as they first appear, and actions taken during a moment of panic are often more disastrous than no action at all. Due to the grace, or perhaps self-interest, of the local power company, businesses often seem to be near the top of the list when it comes to restoring power, and a few minutes to an hour without electricity should be no cause for alarm. Some stores even remain open for business, selling fish and supplies by flashlight and writing up sales by hand.

For longer outages, the most immediate threat to an aquarium’s livestock is lack of aeration. Fish continue to consume oxygen that is no longer being replenished by pumps and aerators and produce carbon dioxide that is no longer being removed. Generally, a tank that is not heavily overstocked or overfed will survive several hours before showing signs of stress., but eventually the excess carbon dioxide and lack of oxygen will begin to damage and kill fish.

To forestall this event, the staff should do as much as practical to reduce oxygen demand in each aquarium. Since certain individual tanks may have a higher fish population density than others, it may be useful to move a few fish to less crowded quarters; perhaps there are even a few fishless tanks that had been prepared for a future shipment that could be utilized.

I’m not sure why even occurs to us (maybe it’s part of a Great American Eating Disorder, wherein some inner voice tells us that food heals all wounds), but fish should not be fed during the outage. Fish can go without food for days, but the increased fish activity and the increased bioload from uneaten food and fish waste can quickly deplete oxygen and put a tank at risk within minutes.

Darkness is a good thing. With the lights out, many fish will slow down and rest, and will use much less oxygen than when they are active. Encourage this behavior by leaving them alone as much as possible. Be observant, but not a nuisance. Covering tanks of skittish fish with towels or blankets will help keep them calm and rested, especially if there is sufficient daylight to allow them to see you and your staff pacing about. Darkness is also a bad thing – at least as far as heavily planted aquariums go. At first, it may seem that lots of oxygen-producing aquatic plants might actually be a solution to declining water quality, but it must be remembered that plants only produce oxygen while they are well-lit. During the darkness, they consume oxygen and produce carbon dioxide just like the fish do. A few live plants per tank won’t likely make much difference, but a plant-selling unit choked with Anacharis or Hornwort might easily have more fish loss than an unplanted tank.

If power is expected to be out for a prolonged period, temperature change may become a concern, especially since many power failures are a result of extremely hot or cold weather. A few key tanks of expensive or sensitive fish may be worth protecting by draping blankets over them to act as insulation. Fortunately, many fish rooms and “fish store” buildings are already well-insulated in order to reduce energy costs and will chill or overheat more slowly than a more typical retail building.

Before power is restored, it’s a good idea to assess the filtration system(s) employed. If the power has been out for more than a few hours, the organic waste collected in the filters may have begun to decay anaerobically (without oxygen), producing foul and toxic compounds like methane and hydrogen sulfide that will pumped into already stressed aquariums. If there is reason to suspect there is a large buildup of waste, the filters should be cleaned before the power comes back on. If that is not possible to do on such short notice, it may be advisable to take loaded filters offline until they can be cleaned, and arrange for some other sort of aeration in the meantime.

When power is finally restored, go ahead and let out a sigh of relief, and perhaps add a few kind or unkind words about your local power company. But the story’s not quite over yet; those stressed survivors need to be watched closely for a few days for ich and other common pathogens that may take advantage of their weakened state. If the tanks had been chilled more than 5 degrees Fahrenheit, a preventive dose of malachite green or other mild parasite controller might be considered, but should not be applied until tank filtration and aeration have been brought back up to normal for a day or two and power is unlikely to fail again.

It’s also possible that an extended outage will have diminished or destroyed the biological filtration system, so ammonia and nitrite should be monitored regularly during the next week. Partial (25%) water changes and sharing decorations or filter media from unaffected systems will help dilute toxins and restore the beneficial bacteria quickly.

Insert 1 – The Mini Failure

Most power loss problems are due to failure of the power company’s lines or substations, and can’t be prevented or corrected by the end user. Others, like loss due to blown fuses or tripped circuit breakers, are more under the control and responsibility of the shopkeeper and staff.

A particularly insidious situation can occur when power is out on a circuit that supplies filtration or heating systems. In such cases, the failure may not be immediately obvious, and huddling or gasping fish may be the first indication of a problem. The cure, of course, is to restore power and remove or repair whatever is causing the short circuit (for example, a soaked pump or cracked heater). How well fish recover is determined by how long the systems were interrupted. An inexpensive (less than $20) plug-in alarm device that sounds when power is interrupted is a worthwhile investment. Install one on each important life support circuit, and stock a few to sell to customers that might want to protect there investments as well.

Insert 2 – Your Customers

Many of your customers will also be experiencing power outages, and they may last longer in residential areas than in commercial districts. Many of the tips in this article apply to the home aquarium as well, and the retailer should be prepared to advise his clients to help insure the health and survival of their aquatic pets.

In addition, inexpensive battery operated air pumps should be stocked in sufficient quantity, even though the whole year’s inventory will probably sit on the shelf for months, then be sold out in two days. For a mere $15-$20 and a couple of batteries, a battery pump can keep an entire tank full of fish aerated throughout the entire outage.

This article originally appeared in

Pet Age Magazine