Aquarium First Aid

Aquarium First Aid

Aquarium First Aid information provided by Sam. Broken tanks, soap spilled in the water, power outages, cats getting in the tanks, shorts in electrical equipment, the list goes on. There are so many things that can go wrong in an aquarium. My last few articles focused on preventing incidents from happening in the first place, but there is always a chance that something goes wrong. This article is meant to cover some of the more likely issues that an aquarist may come across over the years.

First of all, with any accident or emergency, it is important to remember two things: Don't Panic, and have a towel, or maybe three, handy. Panicking won't help your fish at all, and may distract you enough that help doesn't come quickly enough for them. And having towels handy is important to keep the area around the aquarium dry so that when you spill water (and you will, because you're not following the first rule), you don't slip on the floor, creating another emergency.

As with nearly any fish-related problem, the folks on Fishlore are more than happy to help you with any issues you may have, but often the difference in time between you posting the problem and someone responding to it could mean the difference between life and death for your fish. Hopefully, by reading this article, you will have an immediate answer for when the unthinkable happens and something goes wrong with your aquarium.


It's a good idea to have an Aquarium First Aid Kit on hand. That is, things that you may need to help your tank out of an immediate jam.

Spare aquarium filter - Even a small one. Just something to provide water movement and a modicum of filtration should your primary filter break down.

Fresh AC (Activated Carbon) - A staple in some peoples' tanks, others only use it for post-medication or chemical cleanup. AC does wonders to suck stuff out of the water.

Air Check Valves - This isn't so much in the kit as it is already installed in your system. If you have any sort of air pump running, it is important to have an air check valve in the line. This only allows air to flow one way, preventing the escaping pressure in the hose from starting a siphon if the power goes out.

Aquarium Water Test Kit - Even if you don't regularly test your water (and many of us don't once an aquarium stabilizes), you should have a test kit, preferably liquid, on hand so you can test water quality if it becomes necessary.

Hospital tank - A tank with filtration and heat, and that is large enough for your largest fish to live in at least for a little while. If you have escape artists or jumpers, keep that in mind when thinking about the hospital tank.

Appropriate sized fish nets for all of your fish - A large fish should not be caught in a small net, and a tiny fish may get wrapped up and stuck in an overly large net.

Aquarium-safe sealant - Most people have silicone, but I think there are some types of sealant that can be applied while the tank is still wet, a boon in particularly large or delicate setups.

Enough unused buckets (or other container) to hold all of your fish temporarily- Unused is important, as the smallest amount of chemicals may still cling to a bucket that was once a mop bucket, and this may be very harmful to your fish.

Water Conditioner and Ammonia Neutralizer - In case the nitrifying colony dies off, you want to be able to save a tank from ammonia poisoning, and in the case of a need for massive water changes, you want to have a supply of water conditioner (a need anyway) on hand.


What seems like one of the worst things that could happen to your fish is actually one of the easiest for them to survive. I mean, nothing can survive being dipped in bleach, right? That's why they use it to sterilize stuff. The thing is, the deadly ingredient in bleach is chlorine, the same stuff that your water conditioner is made to treat.

Should bleach somehow get spilled in your tank, immediately dose the tank with water conditioner. Fish can't overdose on the conditioner, so be generous, perhaps ten times the amount you would normally put in the equivalent amount of water.

I would suggest doing a 50% water change immediately after dosing the water, just to be sure.

Once you've verified the fish will survive the next few minutes, make sure that what went in the tank was straight bleach. If there were any scents or other chemicals in the bleach, it would be wise to put fresh AC in the filter. This should clean the extra garbage out of the water pretty quickly. After an hour, change the AC again so it doesn't leach the chemicals back into the water as it breaks down.


Only slightly worse than bleach, ammonia can be immediately treated with an ammonia neutralizing chemical. Once that has been done, follow the same suggestions as for bleach. Especially with ammonia, there is the possibility of extra chemicals such as pine scent.


Whereas drinking a cap full of bleach or ammonia would mean severe pain at best for a person, run of the mill dish soap is likely to merely cause some discomfort. On the other hand, to an aquarium, soap means death. Never introduce soap to your aquarium for any reason. Even after rinsing it a dozen times, residue can cling to the aquarium and get into the water when the aquarium is filled again.

Soap interferes with fish's gills being able to pull oxygen out of the water, and even the tiniest amount can be deadly. Still, accidents happen, and soap gets in your tank, the only chance your fish have is extremely quick action on your part. The following is a compilation of ideas put together from various members on the forum here. Unfortunately, I'm not sure any of it has worked, but all is based on solid theory, and none of it has been applied immediately after the introduction of soap. It's often been an hour or more before this could be attempted.

Immediately get them into completely new water. This is one of the only times that I will ever suggest this. Put a filter with lots of fresh AC in the water, and do frequent water changes. If you don't have a spare filter, rinse your current one in a mix of water and bleach (which should break the soap down), then dip in a solution of water conditioner, and put entirely new filter media in.

Once you've pulled all of the fish out, begin rinsing, re-rinsing, and rinsing the tank one more time. Wipe it down with bleach (wear gloves), rinse it out, then let it soak with a dechlorinater solution. Soap in the tank means that you're going to be starting the nitrogen cycle over, so if you have a second tank, you're going to want to do a quick-cycle with used filter media. Otherwise, you may want to consider investing in BioSpira for the occasion of putting your fish back in the original tank. It would also be wise to invest in new gravel, and if you had wood or rock in the tank, you might want to seriously consider introducing it as a new ornament in your garden rather than recontaminating your tank.

Broken Fish Tank

This is fairly straightforward. Get the fish into conditioned water as quickly as possible. If any of the original water can be salvaged, do so, as it will be less of a shock to the fish. Be careful not to cut yourself on the glass, as the bacteria in the water can make for really nasty infections.

The most important thing that many people don't think of is that you want to keep your filter media wet. If your filter can be installed on/in the container you are keeping your fish in, this would be the best way to do things, as it will keep the new container cycled while you find a new tank.

If this won't work, put the filter media in a zipable plastic bag and put it in the refrigerator. This should keep the media colonized for at least a few days. This will save you from having to start a cycle over from scratch.

Shorted Electrical Equipment

If anything leads you to believe that there is a short in a piece of electrical equipment, touch nothing that is wet. Find your circuit breaker and cut the power to the area of the house the tank is in. It's better to be safe than sorry, so if you have to cut power to more than one place to be sure, do so.

After you've cut the power, unplug the equipment and get it out of the tank.

You may want to invest in an aquarium grounder, which functions similar to a lightning rod, and may allow your fish to survive an electrical short. All of your tank's equipment should be plugged into a GFCI outlet! A GFCI outlet can save your life.

Aquarium Power Outage

Power outages present multiple problems. Filtration ceases, heaters stop working and aeration stops working. There is the possibility that air lines begin a backflow, even with a check valve in place. This is the first thing you want to check for, because a siphoning air line could turn into an electrical short if the power comes back on. If water is backing into an air pump, be sure to unplug the pump immediately. Consider getting a battery powered air pump!

Some filters need to be primed after they stop running, so when the power comes back on, be sure to check to see that they are working. I have an old HOB filter that has to have a cup of water poured in it before it will start running, so I need to get to that tank immediately after the power comes on, or the motor will run dry and burn itself out.

If the power is going to be off for a long time, your tank will begin to cool down and waste products will begin building up. At this point, your best bet is to do water changes to keep waste levels down. Pouring the water back will have the added benefit of aerating the water.

Another thing to consider if the power is going to be out for awhile is the filter media. If the media dries out, the nitrifying colony may die off. Again, placing the wet media in a plastic bag and storing it in the refrigerator may be your best bet.

Medicated aquarium filter media / live rock

If you end up medicating a tank with an antibiotic, it is likely to kill off the nitrifying colony. Once the run of medication is over, it is important to run new AC in the filter in order to clean the medication from the water. After the medication is clear (it takes a couple of hours, at most, for the AC to do its work), it would be a good idea to put used filter media into the filter. By thinking ahead, you can solve this by refrigerating some used media or by running an extra filter in a second tank (if you have one). Otherwise, BioSpira is probably your best bet.

Live rock, a natural "filter" for marine tanks, deserves special mention in this. It is best to not medicate live rock, as this can kill the bacteria in it. If you do accidentally medicate live rock, get it in new water as quickly as possible, with a power head pointed at it and, if you have an extra one, a filter with new AC.

This covers some of the possible issues that might come up. If you come up against a problem not listed here, and someone inevitably will, Don't Panic, work quickly, and get your fish in as comfortable an environment as possible. Once that's done, the folks around here will be more than happy to try to help you minimize the damage.

About the Author

Sam started keeping fish when I inherited a tank from a friend's girlfriend. Have since purchased three other tanks, each with an entirely different setup and type of fish.

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