This is urgent for me, so any immediate suggestions/answers are appreciated!

I live in a one-bed apartment with three other roommates in Colton, California. Recently, we installed large tanks with many kinds of fish, including bettas, danios, Corydoras (julies, emeralds, pandas, albinos, peppers, etc.), Harley Quinn rasboras, loaches, ghost shrimp, mollys, snails, etc. There are a total of 40-60 fish between all of us.

We have three tanks in total; one 10 gallon (38 L) tank in the living room, and two tanks, 10 gallon and 20 gallon (76 L), in the bedroom, all filled with water at maximum capacity.

We noticed a few days ago our cat spending a lot of time in the kitchen, and discovered that she was hunting roaches.

Due to my roommates and I's schedules being so different, we are having a hard time figuring out when to bug-bomb our residence. How are we to keep the fishes safe from the bug-bombing when it occurs?

I've read forum after forum; some say "cover the tanks up with a plastic not able to be penetrated by the harmful toxins", some say "remove your fish"; but that's impossible with the 20 gallon tank.

Some say to do a 100% water change when I get back and air out the remaining fumes. I have only seen one other post on here, dated 6 years ago; I was hoping to get an updated version due to people's experience on what the heck I should do?

I'm using the brand Raid No Mess Fogger. Do I cover the tanks and secure them tightly, unplug any line going in or out of it and take the filters with me in the car and hope for the best?

I'd appreciate it so much if you helped me out! It takes a few minutes to respond to a question on a forum like this and if you take just a few minutes out of your day for me to help me out, just know it's greatly appreciated and you are saving a huge load of fishes' lives!

Thank you for your time in advance.

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    How long will the procedure last? How long would the animals need another home? (Depending on the time the other home would be quiet easy (short time) to comparable with the original home (long time)) Mar 15, 2021 at 8:13
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    this is unrelated, and I'm not an expert at all in fishkeeping, but those tanks all sound overstocked! Ten and 20 gallon tanks are actually rather small, and my smaller tank (15) is definitely overstocked with its 10-20 platies (can't help that). After resolving this, please consider upgrading their tanks!
    – Allison C
    Mar 15, 2021 at 13:17
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    And related to the question, why are you limiting yourself only to the option of deploying your own bug bomb? If you're in an apartment, other units undoubtedly have roaches as well, and your management company should handle fumigating all affected apartments as well as any common areas affected (utility rooms, they often move along water pipes).
    – Allison C
    Mar 15, 2021 at 13:30

1 Answer 1


I don't think there really is any safer method of protecting your fish and other animals than physically removing them from the fumigated apartment. I wouldn't trust anything else to be 100% reliable and guarantee their survival.

Please note that, while insecticides are extremely toxic to fish, they are even more toxic to invertebrates - shrimps, snails, etc. If you cannot temporarily rehome all the animals, please at least rehome the shrimps and snails because they are the most sensitive.

However, I also understand that moving even a small aquarium is incredibly impractical and disruptive for the biological balance because it requires removing all the water from it, usually also the substrate; there is also a risk of breaking the glass during transport.

Having said that, if relocating the aquariums nor rehoming the fish are not viable options, you definitely need to isolate the aquariums with airtight barriers to prevent any insecticide fumes from coming in contact with the water. Plastics are not imprevious to all chemicals - especially not to organic compounds as they could still diffuse through - but covering the aquariums even with common plastic foil is definitely better than nothing. It would be really good if you could get hold of a foil made of PTFE (also known as Teflon) to wrap the aquariums in it - this material is the most inert and impermeable of all plastics; containers made of PTFE are used to store especially aggressive chemicals that damage or seep through other materials. PTFE foil might hopefully be available in your local hardware store.

Please note that even using airtight material doesn't necessarily mean that the resulting seal will be completely airtight - and I won't expect it to be, there are probably going to be at least a few imperfections. However, to increase the chances, I definitely recommend using large amounts of duct tape - especially while wrapping the plastic foil around places like power cords of the filter, etc.

It is also essential to seal/disable any airflow inlets that would let the air (and thus the insecticide fumes) in the aquarium - like the air tube of the filter. The filtration itself, however, must stay on in the aquariums - or else you risk breaking the nitrogen cycle and getting a potentially fatal ammonia spike.

As Trond Hansen suggested in the comment, it would also be good to use activated carbon/charcoal (from the pet store) in all the aquariums as a preventative measure against the insecticide. Activated carbon adsorps a lot of chemical compounds, including various toxins. It would be the best to place the activated carbon as an additional medium in the filters of all the aquariums in the apartment before the fumigation - in this case, it should always be placed in a way that the water entering the filter passes first through mechanical medium (sponge, etc.) before passing through activated carbon layer. If it is placed the other way around, the activated carbon would quickly become clogged with larger particulates and this would waste its potential - the carbon would stop being active long before its adsorption capacity was exhausted. If the filters are also using biological media, like ceramic rings, etc. then it is less important as to whether the carbon is placed before or after the biological media.

If it is not possible to place the activated carbon inside the filter as a medium, it could be placed somewhere else in the water column, optimally in a place with high flux of water current. In this case, it is also advised to contain the activated carbon in some sort of "bag" made of aquarium-safe, water-permeable material - for example, it could be wrapped in a layer of filter floss (please ask about this material in the pet store); this will make it much easier to remove all the carbon later. All the carbon must be removed from the aquariums at some point; it is because it will eventually get saturated and from then on it could begin to release all the adsorped substances back into the water column. Please use the information provided by the manufacturer on the package to decide at which point you should remove the carbon from the aquariums.

On the top of that, you must take into account that isolating the aquarium the way I described is going to cut it off from the supply of atmospheric oxygen. It is not going to be a problem immediately, but the oxygen is eventually going to get depleted and it is a huge problem because obviously you cannot expose the aquarium to the insecticide-contaminated air. My guess as to how long would it take to deplete the oxygen in this scenario is anywhere between a few hours to a few days; it is hard to tell because it depends on a lot of factors: bioload, amount of photosynthetic activity in the tanks (which in turn depends on illumination, density and type of the plants), volume of air sealed within the aquariums, etc. For this reason, I would strongly suggest rehoming the fish temporarily - just the fish - this will remove the problem of seal-induced oxygen deprivation in the aquarium and let you focus on sealing the aquariums from the air.

According to the manufacturer's website, Raid Fogger uses etofenprox as its active ingredient. As Wikipedia says, toxicity of pyrethrins in aquatic environment increases with temperature, so I'd advise you to lower the water temperature in all the aquariums to the lowest that is still safe for fish, for at least a week or two. Etofenprox is not a pyrethrin, it is a pyrethroid derivative; pyrethroids are closely related to pyrethrins because they are synthetic analogues of them. This is why I think it is reasonable to assume that this general information from the article about pyrethrins applies to the fogger applied in your apartment.

I am sorry that I cannot do anything more, I really want to help you and your fish, but we are limited by the fact that Pets SE isn't really meant to be a reliable acute-response, real-time emergency help for situations like this.

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    i just want to add this,the op should add acctivated charcoal to the tank to remove the toxins that end up in the water.you can get acctivated charcoal in your petstore. Mar 15, 2021 at 15:12
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    @trondhansen It is brilliant suggestion, I didn't think about this before, I updated the answer, thank you.
    – lila
    Mar 15, 2021 at 22:55

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