# Help needed to solve the cause of dying fish



## krzys (Jul 12, 2020)

G'day all,

Thank you for a great forum. I used to have low tech and high tech tanks. I decided to set up a soil based substrate inspired by Diana Walstad book. I set up soil based substrate 4 ft, 230l tank two weeks ago.

I attempted to introduce fish twice and failed miserably twice. Poor fish die overnight.

In the first week there was no traces of ammonia nor nitrites. So I added 3 fish after a week. Fish were happy, ate algee, no signs of stress. Next morning one was dead, next one died soon after and third one later on. They were labour breathing and gasping for air. I thought there was not enough oxygen. No ammonia or nitrites in water were present.
I monitored ammonia and nitrites levels for next week, and again test showed 0. I added few fish and the same thing happened again. I had water gently areated whole night by airstone with lots of tiny bubbles and a good water movement from the filter. One fish was dead in the morning and the the rest died withing next few hours. I could not see any bad signs on their gills, maybe slight damage on pectoral fins or they were just clumped together. Again no traces of ammonia or nitrites. Poor fish were losing buoyancy before they died.

I used garden soil I bought for my garden 3 years ago. Back than I had some cow manure and blood and bone mixed with soil. No other fertilizer or pesticides were added during 3 years in my garden. Submerged soil in a bottle sample coloured water in yellow, no bed smell.

I looked thoroughly through soil and removed all pieces of bark, leaves and sticks. I have not seen any traces of manure. I put 1 inch of soil and around 0.75 inch layer of gravel on top (3-4mm gravel).
I used big spider wood driftwood that I put on top of acrylic pieces sitting on the bottom glass of aquarium. Driftwood does not sit on gravel or cover it. White fungue or bacterial growth appeared after few days.

After few days i had lots of brown water, barely could see the middle of the tank. It must have been the driftwood releasing tannins. (Soil was giving yellowish colour in the sample bottle). I changed 90% water and put activated carbon in the filter. Tannins were colouring the water slower. Water does not smell as rotten eggs, but have some more sweet smell, I can't figure out what it is. Not exactly typical aquarium water smell. Maybe it is that white stuff covering the driftwood that gives that smell. The white growth is still there after two weeks, but decreasing in size and coverage.

Plants are growing good, snails are going good, some brown algae, and a some hair algae especially on floating plants.
I planted lots of plants straight away. Some bubbles are released from substrate, especially from around were wisteria is growing.

Is it possible that aquarium did not start to cycle or the plants are using all ammonia straight away? If there is no ammonia or nitrites what could kill the fish? Too much CO2 from the substrate, not enough oxygen? Other poisoning, metals, gases? Is it substrate or driftwood or both releasing something toxic to water?
I thought snails would die easier then fish, but the doing well and seem to multiply.

Please give me some ideas what could be going on wrong with my aquarium. I will wait another month more before trying to put any fish there. pH does not seem to swing daily too much, maybe 0.1-0.2. I checked in the evening and morning and mid day. Tap water is not great, 7.6-8.0 pH, 3kH, 4GH. With the second attempt to introduce fish i managed to get the water to 7ph, 4kh and 7gh. It didn't make any difference.

Best Regards,

Kristof

1st photo-set up day,
2nd photo-toouch tannins
3 photo-two weeks after setting up, 90% water changed, did not save the fish.


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## hoppycalif (Apr 7, 2005)

Welcome to APC! That is a very interesting problem!

Did you use a dechlorinator, like Seachem Prime, when you set up the tank, and every time you replace more than 10% of the water?

Where did you get the wood piece? Did you soak it for a few weeks to try to leach out the tanins, etc?

About the only other variable I see is the soil: When a sample of the soil is wet what does it smell like?


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## mistergreen (Mar 3, 2007)

It does sound strange.
Instead of fish, try adding cheap shrimps. They're good indicators if anything is weird with the tank parameters. Fish dying that fast could be from shock. Ask what parameters are where they came from and do a drip acclimation before introducing into your tank.


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## krzys (Jul 12, 2020)

I do use API water conditionee, addbit t the water in the bucket before pouring it to the tank.
Water in the sample doesn't smell. That's why i think it may be the growth n the driftwood giving that odour. I did not soak it, shop said it shouldn't leach a lot, i had it submerged for 2 days with little tannins leaching out so i thought ot was save. Will see how it goes after last water change. I had peat in the filter for the first few days, so the first brow colour was from both peat and wood. Peat didn't lower ph so i took it out.
First time fish were in shop water around 7.2-7.3 ph my tank was 7.8 ph I kept fish in the bag for over an hour and added the tank water there bit by bit. Once in the tank fish were happy, swimming around, playing in current and eating algea.
Second time fish shop had ph 7 same as my tank. GH was not far off in both cases. Fish were happy during first daytime and didn't survive the night, or died in the morning. Henceni thought it was CO2/O2 related.


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## mistergreen (Mar 3, 2007)

CO2 generated in a soil tank isn't too much to kill fish. Your O2 could have been solved with the airstone. For now, I would take out the wood too see.


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## jatcar95 (Oct 30, 2019)

Is it possible your tests are expired or faulty? Have you ever got a reading of ammonia > 0? There's usually a spike of it right after the soil is submerged.


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## dwalstad (Apr 14, 2006)

I suspect that the problem stems from something released from the soil or possibly the driftwood. Who knows what they contain.

Have you done any water changes since setting up the tank?

Since other inhabitants and plant growth are doing well, perhaps this is a temporary problem.

That said, I'm sorry that you lost your fish.


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## aquabillpers (Apr 13, 2006)

What kind of fish did you have? Some species are less tolerant of marginal conditions than others.

Bill


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## krzys (Jul 12, 2020)

jatcar95 said:


> Is it possible your tests are expired or faulty? Have you ever got a reading of ammonia > 0? There's usually a spike of it right after the soil is submerged.


I will check the expiry date on the tests when get home from work.

That is what confuses me, I have had no reading of ammonia or nitrites >0, ammonia test shows yellow (though a brighter than the one on the paper, I can't see any hue of green there), same with nitire (first color, as far as I remember it is blue).

So if my tank did not start to cycle, wouldn't decaying plant leaves, plus adding the fish ( even for a short time) generated enough ammonia to show up in the test? Or the plants would use it up so quickly? I checked ammonia levels in the morning when it was still dark so plants were not photosynthesizing yet.

I could add shrimps (they are not cheaper than fish, same price as cheap fish). Are there any benefit to buy shrimps over fish to test the water? Are they less tolerant or tougher than fish to any toxins, O2/CO2 problems? I've never had them before.

I added Siamese algae eaters after one week of setting up the tank (which died next day or overnight). After 2 weeks from setting up the tank I added few lemon tetras (also died overnight or in the next morning). I have currently no fish in the tank. The snails are multiplying and growing so far with no problems.

I hope the problem is temporary, I will keep everything as it is and wait a month or so before adding any fish.

I did 75% water change after 5 days, 50 % WC after a week and 85% WC after 2 weeks from setting up (yesterday). The 3rd photo is after the last water change.

I was wondering, if there are any toxins in water then activated carbon should remove them or am I worng here? Also, what is weird all snails are doing well. If there were any toxins released from soil or driftwood, I thought, snails wouldn't be alive by now. That's why I was thinking of soil CO2 poisoning combined with substrate using available O2 during the night. Maybe the airstone was not providing enough oxygen.

I have never had this problem before.


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## Red_Rose (Mar 18, 2007)

krzys said:


> I could add shrimps (they are not cheaper than fish, same price as cheap fish). Are there any benefit to buy shrimps over fish to test the water? Are they less tolerant or tougher than fish to any toxins, O2/CO2 problems? I've never had them before.


Have you ever heard of the canary in the mineshaft? Back in the day, miners would bring a canary in a small cage down into the mineshafts with them because birds have sensitive lungs. If the canary died, they knew that there were dangerous gases in the mine.

Shrimp are the canaries of the aquatic world. They are much more sensitive to problems in the tank than fish are which is why they were recommended to you. If the shrimp die in your tank, you'll know that there is something going on.

About the water testing. Try taking a sample of your tank water to a LFS. They can test it for you. That way, you can see if your test kits are faulty or not.


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## hoppycalif (Apr 7, 2005)

I would remove the wood piece and put it in a large container so I could soak it in hot water every day for a couple of weeks or more. That is a lot off wood surface, so if it was treated with something by the seller it could cause big problems as whatever it was started leaching out. I think the odds are very high that it is the wood, and not the soil, that is the problem.


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## terryna (Mar 16, 2018)

mistergreen said:


> CO2 generated in a soil tank isn't too much to kill fish. Your O2 could have been solved with the airstone. For now, I would take out the wood too see.


very nice


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## krzys (Jul 12, 2020)

Thank you for your advise. It is unlikely that the test kits are wrong. I tested tap water with the results of 0 for both ammonia and nitrites and exactly the same color as when I tested the aquarium water. Test's expiry date is 2025.

I will get the red cherry shrimp (the only available type of shrimp in the city) and see how it goes.


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## dwalstad (Apr 14, 2006)

Looking again at photos of your tank and hearing about all the tank maintenance (frequent water changes and charcoal addition) made me rethink....

I don't think it's the soil, ammonia or nitrites. I agree with hoppycalif that it is probably the driftwood. Driftwood causes more tank problems than people realize--or will admit. Your driftwood is huge with a huge surface area. The water cloudiness and release of tannins indicates that it is reacting and not inert like it should be. The tannins themselves could be toxic. I would remove it from the tank, at least temporarily, change the water, and add some fish.


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## Karen in San Jose (Jun 1, 2020)

I will just add that I once put the incorrect amount of API tap water conditioner in my tank and it killed off a lot of the backworms living in the tank. Not all of them, but a lot of them. Then shrimp and snails in the tank ate them, so it wasn't the end of the world.

But, what this taught me is that tap water conditioner isn't completely benign. And, it doesn't say on the bottle what's in it. 

In my opinion, if you can't make a mistake in your calculations without killing something in your tank, the bottle should give you some kind of heads-up that there are toxins in the formula.

I have stopped using tap water conditioner completely because of my experience. I just keep a stash of tap water in gallon containers open to the air, where they can evaporate chlorine, etc. I just think it's safer, and I haven't had any problems with my tank since I started doing this.


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## mistergreen (Mar 3, 2007)

Karen in San Jose said:


> I have stopped using tap water conditioner completely because of my experience. I just keep a stash of tap water in gallon containers open to the air, where they can evaporate chlorine, etc. I just think it's safer, and I haven't had any problems with my tank since I started doing this.


You can use vitamin c to remove chlorine too. It's pretty safe, lowers your pH slightly. 1gram (1/4 tsp) will treat 1ppm of chlorine in 100 gallons. Vitamin c will also boost your fish's immunity so it good.


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## mysiak (Jan 17, 2018)

Karen in San Jose said:


> I will just add that I once put the incorrect amount of API tap water conditioner in my tank and it killed off a lot of the backworms living in the tank. Not all of them, but a lot of them. Then shrimp and snails in the tank ate them, so it wasn't the end of the world.
> 
> But, what this taught me is that tap water conditioner isn't completely benign. And, it doesn't say on the bottle what's in it.
> 
> ...


Just a word of warning, chloramine does not evaporate and is pretty stable for quite a long time. Some water treatment facilities switched from chlorine to chloramine and it can't be easily removed.

As far as I know, water conditioners use reduction chemicals - when overdosed they will cause oxygen depletion, that's why it's important to follow the instructions on the bottle. Some are safer than others, but there is a risk with all of them.

As a preventive measure I always dose a bit of hydrogen peroxide after water change to counteract the side effects of water conditioner.


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## dwalstad (Apr 14, 2006)

Excellent input Mysiak! Didn't know about the oxygen/H2O2 aspect.

I would not put down water conditioners. If your water treatment plant uses chloramines, I believe that they are absolutely essential. So many hobbyists in my area have had heart-breaking fish kills after a water change. Sometimes the city water treatment plants will suddenly increase their chloramine levels and these hobbyists were caught off guard.

First thing, I would find out whether your water treatment plant uses chloramines--or plan to. Most do these days. If so, use a water conditioner, especially for large water changes.

_You can get rid of chlorine gas by letting water sit in a bucket overnight, but not chloramines._


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## Karen in San Jose (Jun 1, 2020)

Thanks so much for the information about chloramine not evaporating. I checked my municipal water supply and chloramine is not used in my area, fortunately. But, as mentioned, who knows if they may change their minds.

I did research and learned that tap water conditioners can leave ammonia behind. I found this article helpful.

http://www.theaquariumwiki.com/wiki/Water_conditioners

It looks like API tap water conditioner doesn't neutralize the ammonia it can create when it breaks down chloramine, but API Stress Coat water conditioner does contain the chemical that neutralizes ammonia.

I happen to have bottles of both kinds. I think going forward I will treat the water, just in case they decide to also start using chloramine in the water for my neighborhood, and use the API Stress Coat conditioner.

You sure don't want to make a mistake in measuring the dosage, I learned. These are serious chemicals. The API product info sheet has all kinds of warnings.

No room for error, I learned. But, as you say, it's important. Always more to learn!


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## Red_Rose (Mar 18, 2007)

Karen in San Jose said:


> I did research and learned that tap water conditioners can leave ammonia behind.


Have you considered using Seachem Prime? You need very little to treat the water and some people even use it to detoxify ammonia and nitrite. It's the only water conditioner I use.


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## mysiak (Jan 17, 2018)

Red_Rose said:


> Have you considered using Seachem Prime? You need very little to treat the water and some people even use it to detoxify ammonia and nitrite. It's the only water conditioner I use.


Seachem prime and safe use Sodium thiosulfate, which detoxifies chlorine and chloramine, but it does not bind or detoxify ammonia or nitrite (or heavy metals). There is no scientific evidence to back up claims made by Seachem, even they base it on anecdotal evidence from customers and openly admit that they don't understand how it works, but "it just works".

Sodium thiosulfate is very good at chlorine and chloramine detoxification (ammonia released during the process is consumed by filter and/or plants), but it has a higher risk of removing also dissolved oxygen when overdosed. Vitamin C is a safer option.

Edit: actually it contains Sodium dithionite which converts to Sodium thiosulfate in water solution. Source (interesting reading): https://aquariumscience.org/index.php/5-5-3-1-ammonia-detoxifying/


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## krzys (Jul 12, 2020)

G’day all,

Thanks again everyone for your replies. I thought I post updates on my tank situation and hopefully it will help other people to avoid my mistakes. Long story short I introduced fish and they are alive.

I did not remove the driftwood as many of you suggested. Unfortunately, I don’t have big enough container to soak and boil the driftwood. I would have to cut it and later somehow put it back together and reattached all java fern, moss and anubis. So I left it in the tank and continued to use activated carbon for another 1.5 weeks. The water stayed pretty clear even after I removed activated carbon from external filter. It has only a slight discoloration now. After the second big WC (90%) the weird smell and tannins practically disappeared. Water smells like a normal aquarium water now. I think the smell was from the growth on the driftwood. After the 90% WC it did not build up to the same level and I could only smell the traces of this for a week.

I thought the peat moss I used for the first few days in the external filter have had some additives. In that case peat moss could have released toxins. The distributor confirmed it is a pure peat moss from New Zealand with no fertilisers, fungicides or any other additives. So it could not release any toxins to kill fish.

The driftwood did not release any toxins that would kill snails or shrimps, so if there were any kind of toxins leaching from driftwood they would have to target fish only. I find it to be rather unlikely, but I might be wrong.

I am still leaning to the theory that lack of oxygen killed my fish. I don’t know if peat and driftwood did or didn’t leach something bad to the water. It could just have been another contributing factor that by itself was fine, but with low oxygen levels stressed further the fish. What I have learned from research is that the bacteria/fungi growth on the driftwood use a lot of oxygen. There was lots bubbles coming out from that growth so the gas exchange was happening within that film on the driftwood.

Fresh submerged soil uses a lot of oxygen, additionally a big driftwood having big surface area covered with the growth must have also used a lot of oxygen. Both equals oxygen deprive water during the night and that probably was enough to kill fish through the night or stress fish enough that they couldn’t recover the next day.

So what did I do wrong?

1.	Did not properly prepare peat moss.
2.	Did not properly prepare driftwood.
3.	Did not take into account what fresh soil and growth on the driftwood does to the oxygen levels in the tank during the night.
4.	Didn’t oxygenate the water or didn’t oxygenate the water enough during the night after adding fish.

On the positive note a few words on the tank inhabitants. Few days after 90% WC I added 6 red cherry shrimps (thank you mistergreen for your suggestion, I really like them). Few days later I added another 18 RCS from a different breeder. Few days later I added 6 peppered corydoras and another 4 some time later. The corydoras felt like at home straight away and showed no signs of stress. Last weekend I added 9 lemon tetras. So far so good. Ammonia and nitrite levels are zero. Snails are multiplying, RCS are growing, molting and grazing. Plants are doing very well except one floating that possibly doesn’t like high pH of 7.6-7.8. The other floating plant is doing ok. No problems with algae so far. I attached tank picture from taken couple of days ago. All fish decided to hide from camera.


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