# Fish dying in new tank - wrong background foam or silicone?



## oilen (Mar 5, 2010)

Tank has been cycled for almost a month but I continue to lose fish, nobody lives over 6-7 days. My latest though is that the type of foam I used may be leaching some toxin. I did not use styrofoam brand what I used is EPS polystyrene which is used typically for roof and wall insulation. I downloaded an MSDS sheet from the manufacturer and for you chemists out there it contains: Polystyrene (95% of makeup), Pentane, Hexabromocyldodecane, Disodium Octaborate Tetrahydate. Under the toxicity section it does say that product is "predicted to have low toxicity to aquatic organisms" Any thoughts on other possiblitlies? Thanks


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## Rhinox (Sep 10, 2009)

hmmm... did you use concrete for your background? If so, test your pH. Concrete can drive pH super high until it cures.

Whats in the tank as far as substrate, rocks, decorations?

Whats your nitrate level? Have you tested ammonia and nitrite just to be sure? Have you tested pH and KH lately? if you have low/no KH, your pH may be crashing.

Its the 340g in your sig right? is it glass or acryllic, or is it DIY plywood or something else?


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## oilen (Mar 5, 2010)

I used water based Dryloc for the background.

I have had no hint of ammonia in 6 weeks, Nitrate 0, Nitrite .10

Kh reads low with test strips but the Ph has remained constant 7.8, will low Kh kill fish?

I have play sand base with rocks that came out of another healthy tank.

???


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## Chubbs the Jellybean (Jun 16, 2009)

NitrAtes should be around 5-15ppm, not zero, and nitrItes should be at 0


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## Rhinox (Sep 10, 2009)

*will low Kh kill fish? *
no, unless the low KH cause ph to crash - doesn't sound like thats happening. My KH is low as well, and my pH is on the low end, but fish don't seem to care.

*I have had no hint of ammonia in 6 weeks, Nitrate 0, Nitrite .10*
This makes me wonder. Any ideas why your nitrate is 0? Have you been doing big water changes or something?

I might try a few days of adding 1-2ppm ammonia at the same time each day, making sure ammonia and nitrite are 0 just after 24 hours, and by the end you should be seeing 10-20 nitrate. Though, I would suspect that if your tank wasn't cycled, then there would be ammonia or nitrite in the water from the fish you've been trying out in the tank. Still, just trying to check the box as definitely not the problem.

Playsand and rocks don't sound like they should be the problem.

hmmm... What was the silicone that you used to adhere your background to the tank? was it aquarium safe? was it fully cured before you filled with water?

Do you have chlorine? what do you use as a dechlorinator/water treatment?

ummm... idk, I'm running out of ideas. Was the tank new or used? How was it cleaned before you set it up? And chance of residual chemicals (either that you might have used, or might not have cleaned thoroughly enough from where you bought it) in the tank when you filled it the first time?

Same with the foam. I really don't think the foam itself is the problem, but is it possible that there could have been some residual chemical on it before you placed it in the tank?

Only other questionmark I can think of is something else in your water out of the tap. I'm thinking like maybe copper or other heavy metals?? Maybe you can test for it by adding a conditioner that neutralizes heavy metals and see if the fish survive, if you can't find a way to test the water for it directly.

Oh, last thing - any chance the fish you are buying from the petstore are so mistreated that they're on the verge of death before you get them home?

just grasping at straws, now...


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## fmueller (Jan 11, 2004)

oilen said:


> Nitrate 0, Nitrite .10


99 times out of 100 somebody posts something like this it's a typo meaning nitrite 0, nitrate low, which is the way it should be.

I don't think it's the foam or any of the other materials in your tank. How recently have you added fish? Could they have been sick or parasite infested? How are they behaving? Are there any signs of trouble before they drop dead?


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## newforestrob (Feb 1, 2010)

didnt want to start a new thread for this...what silicone should be used? ...sorry if its a given,well known thing


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## fmueller (Jan 11, 2004)

newforestrob said:


> didnt want to start a new thread for this...what silicone should be used? ...sorry if its a given,well known thing


Silicone without mildewcide is aquarium safe. It's usually sold under the label 'for door and window'. Silicone 'for kitchen and bath' has mildewcide, and is not safe.

Confusingly there is also a difference between Silicone I and Silicone II, but that has nothing to do with mildewcide. In the curing process, Silicone I gives off acetic acid (vinegar), while Silicone II gives off ammonia. Both chemicals are harmful to fish, and whatever silicone you use, you want to make sure it is cured before you expose it to water with fish. Silicone I and II also have differences in adhesion strength for different materials, but for aquarium purposes, this is largely negligible.

In short, whether you buy Silicone I or Silicone II does not matter, but make sure to buy the version without mildewcide, which is labeled 'for door and window'.

The amount of misinformation about this issue on the web is mindboggling


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## newforestrob (Feb 1, 2010)

phew...thanks for that information,I read somewhere that silicone 11 ,should be used,I used silicone 1 ... for doors and windows :thumb:


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## oilen (Mar 5, 2010)

Okay thanks for jumping on this thread regarding the silicone. Mystery solved? I have read here on other threads and about using GE silicone I, which I used, but never saw any comment on door and window vs. Plumbing GE Silicone I. Of course I used the plumbing one to adhere my background. Please tell me I don't have to start over and that this will eventually leach out with water changes?


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## The Novice (Jan 27, 2011)

When all else fails, put in a couple dozen goldfish, and wait for the nitogen cycle to stabilize. If the gold fish die, you have a serious problem!


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## oilen (Mar 5, 2010)

Has anyone ever used the wrong silicone and will time and water changes be enough to ever get the water safe? I used GE Silicone I to adhere a foam background as recommended here but I guess it has to be the one for windows and not tub and tile.


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## Nina_b (Jan 3, 2011)

as long as it doesn't contain fungicides, it should be fine, no?

Someone who knows jump in here


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## fmueller (Jan 11, 2004)

The Novice said:


> When all else fails, put in a couple dozen goldfish, and wait for the nitogen cycle to stabilize. If the gold fish die, you have a serious problem!


Or you bought sick gold fish from a chain store 



oilen said:


> Okay thanks for jumping on this thread regarding the silicone. Mystery solved? I have read here on other threads and about using GE silicone I, which I used, but never saw any comment on door and window vs. Plumbing GE Silicone I. Of course I used the plumbing one to adhere my background. Please tell me I don't have to start over and that this will eventually leach out with water changes?


Do you have one of the silicone bottles left? What does it say on the bottle? If it says: "Cured Sealant Is Mildew Resistant", you got the wrong stuff. If it says nothing about mildew resistance, you are fine.

That all said, I have read reports from people who have used the mildew resistant silicone, and observed no ill effects to their fish. Whether those fish were particularly hardy, or the owners just not very observant, one will never know. With the mildew resistant silicone you are definitely taking a risk. And if you think about it, the mildew resistance is supposed to kill fungus in a bathroom environment for many years. Doing a few water changes will have the same effect as having a few showers, and the stuff is designed to withstand daily showers for many years...

Despite all this, I'd still love to know where you got your fish, so we can assess the chance of them being diseased before they ever got into your tank.


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## GTZ (Apr 21, 2010)

If it were me, I'd take it out and do it again. I have no idea how lethal it could be to fish, but it does have an anti-mildew or anti-fungal additive in it. Whether or not it leaches into the water once cured, I don't know.


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## Rhinox (Sep 10, 2009)

> Despite all this, I'd still love to know where you got your fish, so we can assess the chance of them being diseased before they ever got into your tank.


I saw he mentioned Petsmart in a different thread a while back...



oilen Wed Jan 5th in another thread said:


> Okay i'm back. Pretty confident that my cycle is complete Ammonia & NO2 have been 0 with NO3 20 ppm for over week. *So I bought 10 silver dollars for a buck at Petsmart day one fine, day two won't eat, day 3 all dead.* levels remained constant all 3 days. So I'm wondering if I have some other poison in the tank. Maybe the dryloc, or the pvc glue in the UGJ piping. Any thoughts?


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## ridley25 (Jan 5, 2008)

If you've used the wrong kind or aren't sure, I'd redo.

kevin


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## fmueller (Jan 11, 2004)

If you used the mildew resistant silicone, it is in no way sure that it will kill your fish. The stuff that makes the silicone mildew resistant will be a fungicide, and fungicides are frequently used in fish tanks, for example to prevent the formation of fungus on eggs.

The fungicide used in silicone might have a certain toxicity for fish, but if it will be lethal, or have any effect at all, will depend on a variety of factors. For example different fish species might be affected to a different degree. As an example, due to their scaleless skin, catfish tend to be particularly susceptible to any kind of chemical in the water. In addition, your tank size and the amount of silicone you used will matter. If you just sealed a small bulkhead in a 300G tank, there is probably no need to worry. However, if you put a whole rock background in a 55G, using multiple cartridges of Silicone, that might be a more serious problem, because the resulting concentration of fungicide in the water might be quite high.

In the end, nobody can tell you what to do. It is safer to use silicone without fungicide, but if it's a lot of work to rip out your background and remove all traces of silicone - I cannot imagine having to do that in my 240G! - then maybe let the tank stand for a few weeks just with water to leach out fungicide and let the silicone cure. Then try the tank with some guppies. If they survive, you can re-introduce cichlids. I am sure they'll appreciate finding some snack food in the tank when they arrive. :thumb:


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## oilen (Mar 5, 2010)

Thanks all. I think because of the hours I have into the back ground i'm going to try extensive water changes for a few weeks and try again. The tank looks fantastic, I'll post pics once it's finally "alive".


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## fmueller (Jan 11, 2004)

Best of luck!


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## wheatbackdigger (May 11, 2008)

How long did you let the silicone cure before adding water? This may be your problem despite what silicone you use. I'd drain it, let it dry out for a week and start your cycling process over. "Uncured" silicone is extremely toxic.


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## jturkey69 (Jun 6, 2011)

fmueller said:


> newforestrob said:
> 
> 
> > didnt want to start a new thread for this...what silicone should be used? ...sorry if its a given,well known thing
> ...


Thanks for this thread!!...I bought 100% silicone 1 (red and white tube)one for kitchen and bath, and siliconed some pieces of small flat rock together to make a small cave/bridge work for a partial foundation of building a rockpile for my african tank, and wifes SA tank. After 5 days of it sitting in the garage, I could hold it to my nose, and still smell the silicone... even after poking small pin holes in any larger globs that may not have cured, so as to give them a chance for more air to get in there....so I figured I would search some more...and finally found this thread!!! I went back to the store to get the ge silicone 1 for door and window... blue and white tube...(NO GOLD lettering or graphics) I will try this with another small stack of rocks, and all should be good, but I will still do the sniffer test..lol. We have a 10 gallon that we could use with a fish or two to test after fully cured, and rinsed in the sink.

Thanks all!


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