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HELP - My tank is toxic and it is killing my fish... but not my shrimp...

2102 Views 11 Replies 6 Participants Last post by  raven_wilde

So I have two ten gallon tanks set up for breeding. Several months ago I did a water change and ran some parameter tests on both of them and within hours afterwards the half dozen Celestial Pearl Danios that I'd had growing out in one of them were dead... the few that I found in their last death throws were gasping on the gravel or hanging among the plants... their fins were ragged with a whitish material. They were all dead by the end of the day, even the few that I tried to resuscitate in a bucket of water from another tank.

The other ten gallon, in which I have some Maculatas was totally unharmed.

After going over it in my mind the only thing that I can think of that went wrong is that I probably got some of the testing solution from my Ammonia or Nitrite test in the tank. I came to this conclusion because although I did all the same stuff to both tanks I performed the tests on the affected tank after I performed the tests on the unaffected tank. My guess is that even though I had rinsed the test tubes in tap water after the first batch of tests there was still some chemicals left in the tubes and when I rinsed them in the tank water (n00b mistake I know, I am ashamed) to perform the second round of test.

As you can imagine I have instated much stricter testing procedures and the test tubes or solution now go no where near my tanks.

After that die off I performed a massive water change and let the tank run for about a month... it has a ton of plants in it and I wanted to see if things would settle out by themselves. Eventually, I put some cherry shrimp in the tank as test pilots. Surprisingly, they did fine and lived in the tank for the next month. They even had babies. I had thought that my troubles were over so I decided to move some of my CPD adults over from another tank to see if things really were back to normal.

Unfortunately, I was wrong. Again, I had a massive die off within hours - the symptoms were the same as before. Also, even though they had lived in the tank for a month or more prior to this, once the fish started to die the shrimp all followed suit.

Current Problem - Disinfecting this tank

Does anyone have any idea what is still going on here?
What is it that is killing my fish? Why were the shrimp okay?

Also, obviously,
I need to tear the tank down and completely clean it out but how far do you think I should go?
Should I throw out all its contents? The gravel? The plants?

Is their a way to disinfect the sponge?
I'd be okay throwing out the gravel and the plants but I am kind of annoyed at the thought of having to toss the poret sponge for the mattenfilter I have running. Its such a pain to have to order another one.

Anyhow, thank you all very much in advance for you help... I feel like such an idiot and this has been such a setback. :icon_sad:
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I had the same problem in my 10g shrimps tank. Water parameters were fine; tank was cycled with media from another established tank. All the fish, even hardy ones, where dying off in a few days to a week while the shrimp were as happy as could be. My problems ceased after I got rid of a suspect piece of wood that was slightly rotting/ growing some whitish fungus inside the tank. Leads me to think the reason might have been fungal...

Now my shrimp share the tank with some White Clouds and a albino dwarf pleco.
Some actual readings on the test results will be very helpful in suggesting what might have happened. Sometimes it is the intersection of two items which come together to make a tank toxic.
What I have in mind is something I get off a chart by Mardel. I don't often trust any single source of info but tghen I find it does pay to listen many times. Their chart shows ammonia which we often think of as truly bad can be safe as high as 6 PPM at low PH levels like 6.0 to 6.4 but rapid death at ph of 8.0. Sometimes what we are used to calling "fine" is not "fine" when other parameters change.

More specific info available?
Some actual readings on the test results will be very helpful in suggesting what might have happened. Sometimes it is the intersection of two items which come together to make a tank toxic.
What I have in mind is something I get off a chart by Mardel. I don't often trust any single source of info but tghen I find it does pay to listen many times. Their chart shows ammonia which we often think of as truly bad can be safe as high as 6 PPM at low PH levels like 6.0 to 6.4 but rapid death at ph of 8.0. Sometimes what we are used to calling "fine" is not "fine" when other parameters change.

More specific info available?
That is a great chart.

It scareD me bc my tap water is 7.8+
It sure depends on what the chemical is that is in the tank. All I have are some suggestions, no answers. Weird how the shrimp are fine, but fish die.

1) If you think it was some reagent in the test kits then contact the company that made the test kit. Explain that you think that is what happened, and have them suggest a way to remove that material.

2) Activated carbon has a pretty good affinity for many dyes, perhaps some of the color-reacting materials in the test reagents. I do not know, but I would start by running AC in the filter, and changing it out weekly. Also look into all the *zorb sorts of things you add to the filter. Cuprizorb, Phoszorb and others.

3) Even though they seem the same, could the deaths be from different causes?

4) Some ways to disinfect aquarium equipment if you suspect a disease:

Remove and throw away plants. If something is on a plant there is no way to sterilize the plant without killing it. Alternatively you can use any of several materials at very weak doses, keep the plants alive, but not know if you are killing the disease. (Bleach, hydrogen peroxide, Excel, potassium permanganate, other)

Thoroughly clean the whole system to remove all possible organic matter, loose and biofilms. Scrub all surfaces.
Run the full set up with chlorine bleach. One possible dilution is as weak as 19 parts water to 1 part bleach. I would go stronger than this.
Thorough rinse, then run the whole thing with a double dose of dechlor. If you cannot smell bleach that is fine, otherwise 100% water change and run it again with another double dose of dechlor.
Then wipe everything down with rubbing alcohol. Use a tooth brush or other small tool to get into every corner. Air dry, even setting everything out in the sun and rotating it. Rubbing alcohol evaporates.
I understand how Poret might be something you want to save. You might contact the company and see if the material it is made of tends to grab unknown chemicals, and if you can sterilize it against possible disease organisms as I have described. I would throw away all other media. Cheaper to replace it than to have to go through all this again.
I know you can treat gravel, rocks and sand this way (bleach, rinse, rubbing alcohol, expose to sun), but I am not sure about many other substrates. The softer, porous ones might take in some of the chlorine for example, then release it later into the tank.
Driftwood can be boiled, baked or run through the dishwasher (no detergent).
To bake driftwood: Put it in a low oven (250*F) while it is very wet. Bake until it is dry. The steam of the water getting boiled out of it is that thing that kills a lot of disease organisms. You can do this to potting soil, but it can stink. If you can cook it outside that is better.
You can build (very easy) a solar over, and solarize most of the substrate, filter media, driftwood and rocks from an aquarium.

When all that is done wash it all over again, then set it all back up again and run the fishless cycle, but keep some activated carbon in the filter, and keep changing it out just in case some chemical has made it through the process.
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This sounds like it calls for a tank breakdown and a bleach rinse of everything.

Then of course rinse with lots of Prime.
On reading through this again, I might add something else. You are looking at changing out the sponge on the thought that it might have something in/on it. There is a way to go that might work or might totally destroy the sponge.
It might pay to do some reading on chlorine first to get a better feel for what it does. Also for what it does NOT do. You will feel better if you read it rather than depending on what some of us might say. Get reliable info, in other words. I might be a bleach salesman needing a commission!

What I find in reading is that chlorine is normally a gas. It has to be tied to a salt to make it easier for us to keep it in a handy liquid form. Whether dealing with chlorine in the laundry, pools or other places, it has one thing most people notice. It smells pretty strong. That is because it comes out of the solution very easily and blows away as a gas. That makes bleach a really handy thing to use. It reacts with almost everything to clean it and then blows away as it dries. When water companies work on things like water towers and want to clean them up after having a few welders walk around in them, the government agencies in charge of our health say to put "x" PPM in and let it set for 12-24 hours.
If bleach is good enough to clean up after a bunch of construction workers well enough for us to drink the water, bleach will have no trouble cleaning your equipment and making it safe to use. It just needs to be rinsed and then let it dry so the chlorine will blow away. Totally dry! If you still smell bleach, dry it some more.

The downside? The bleach may eat up the sponge, but then if the choice is to replace the sponge or TRY to save it, I would try to save it. In a ten gallon tank, a half cup of unscented cheap bleach and soaking overnight will get it all clean. The gravel can be saved as well but it is a real pain to dry gravel. It can be done but a time consuming pain to dry.
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Thank you everyone for the thoughtful responses and information...

PlantedRich, do you have a link for that chart from Mardel?
- I don't *think* that an ammonia spike was/is my problem (at the very least not the first time) since the tank water tested at around 6.4 ph. Also, when the first rapid die-off occurred the fish had been in that tank for several weeks living quite happily without a problem. Anyway, I'd still like to have a look at that info.

Well, I guess I will be tearing everything down. I may try to save the poret... I will definitely contact Swiss Tropicals and ask him what he thinks I should do though. If its a no go I will just suck it up and order another sheet.

I think I will also run some carbon and -zorb products in a filter once I get everything back together. At this point it can't hurt to be paranoid.

Thanks again every body :)
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I don't have a link as it was just from reading a small booklet that I had saved for whatever reason. This is the chart from the book, however. It also may pay to look at the temperature as that also changes the effect of ammonia and the amount of O2 in the water.
This is the chart from Mardel I was reading.

Things I had read but forgotten.

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At your reading of PH 6-4 , this chart would seem to indicate you would have been able to walk on the ammonia before it caused quick death. Sometimes it is just a mystery but it would be nice to learn something for such a high price.
That chart looks clear, but each fish species, and the age of the fish are more or less sensitive to ammonia.

As a general guide keep the ammonia under .25 ppm with water changes and ammonia locking products.
For fish or other livestock that are more sensitive, or fry, keep it even lower.

I do understand that ammonia is in the form of ammonium (NH4) at the low pH in this case, but still, I would try to get rid of it (find the source and correct it, and do water changes) if there was any reading above zero.

Yes, bleach will evaporate, in time (and a fairly short time) if it is exposed to air. Some parts of the aquarium set up are not so well exposed, so run the dechlor once or twice, then finish by allowing any remnant to evaporate.
As an example, when most water companies used chlorine, not chloramine, aquarium keepers could aerate the water for 24 hours and it would be fish-safe. Note the key is to aerate it, stir it, turn it over... so the chlorine was exposed to the air.

Sure hope you figure out what happened!
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Update for anyone reading this for information:

I contacted Stephan from Swiss Tropicals (who is awesome) about disinfecting my poret and this is what he had to say:

Here is what I would do:

First rinse it very thoroughly to get the mud out.
Prepare 10% bleach (1 part bleach 9 parts water)
Stick the foam in for 10-15 min (don't leave it longer)
Rinse and set up the tank as usual. The remaining bleach will dilute and evaporate after half a day.

That gets it >99% sterile.​

I am going to do this later today so I'll let you all know how it goes down.
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