Fish dying when do a water change

[dw1305]

Hi all,

What is old tank syndrome?

It is <"when you don't change any water"> and nitrification (the conversion of NH3 to NO3) depletes the carbonate hardness.

cheers Darrel

 

[dw1305]

Hi all,

10. Drop Checker. - what is this?

It is only necessary when you add CO2 <"Co2 Measuring using a Drop Checker!">.

cheers Darrel

 

[LMuhlen]

While I don't think there is enough information for a conclusive answer, I see the line of thought of an issue with oxygen strengthened by the following:

Double dose of prime
water surface covered with duckweed
Fish selection that might be particularly vulnerable to a lack of O2

On the other hand, if those are the fishes that survived, maybe the conclusion should be the opposite?

Please inform us how much water was changed. Did you dose prime for the entire tank or for the replaced water only?

 

[Myrkk]

I found some chilli rasboras last night, so the fish that did survive varied wildly in size.

5 buckets of water, normal sized buckets, so what, they hold around 7litres. I would say it was a fifth of the tank (200L). The replaced water had enough prime for the 200L tank

 

[Myrkk]

Hi @Myrkk.

My water supply is also Roseberry A. Chloramine isn’t being dosed into that supply regularly. In fact, I top off my tanks and fill up my pond with water straight from the tap without adding a dechlorinator. I’ve forgotten it once or twice on a 50% water change (including recently) and no negative effects have been seen. While this isn’t good practice it does add food for thought on your problem.

I think there’s something else going on here.

Hi Simon,
that’s great to know. TY. It is making me lean towards there being an issue with the water supply in the house, old pipes or some such. We obs drink that water so I think we need to get the water to the house tested now. It’s a 300yr old cottage which was renovated in 2002 by the looks of the history left behind so perhaps something was left in situ that should not have been.

 

[simon_the_plant_nerd]

Hi Simon,
that’s great to know. TY. It is making me lean towards there being an issue with the water supply in the house, old pipes or some such. We obs drink that water so I think we need to get the water to the house tested now. It’s a 300yr old cottage which was renovated in 2002 by the looks of the history left behind so perhaps something was left in situ that should not have been.

You can’t live too far from me so if you would like to do a comparison of your water and mine, I’d be happy to help you out. I have a TDS meter and some various test kits which I wouldn’t necessarily rely on for quantitative measurements but will do for a comparison between the two waters, just to see if there is any difference.

Should give you an idea if there’s something leaching into the water from your pipe work.

 

[ElleDee]

5 buckets of water, normal sized buckets, so what, they hold around 7litres. I would say it was a fifth of the tank (200L). The replaced water had enough prime for the 200L tank

I think you may be deoxygenating your water with too much prime. You may not technically be violating Seachem's instructions on the bottle, but you've got a number of things going on that may be working against you that may be resulting in a functional overdose.

You are dosing to your full tank capacity, not to your water volume (and the best practice is to only dose the new water coming in), so you are using more Prime than needed. Your water likely has less chlorine/chloramine than the 1 ppm assumed for the standard dose, so more prime is left over after handling the chlorine to attack other things in the water, including oxygen. Seachem actually recommends using half the standard dose if you have well under that 1 ppm. Lastly, if you haven't been doing regular maintenance, your water might have low oxygen to begin with, so you don't have much of any buffer against excess Prime.

Let's do some math. I'm going to round your bucket up to 8 L and say you are just treating the new 40 L of water at that half dose. That would be 0.5 mL of Prime per water change compared to the 5 mL (or 10 mL for a double dose!) you have been using. A whole order of magnitude different! I think that could result in a catastrophic oxygen depletion and kill fish.

I don't know that this is THE problem, but it's plausible and worth investigating because it would be easy to fix - certainly easier to address than toxic house pipes.

 

[azawaza]

I'm sorry for your loss, but this thread reads much like a case on House MD (imagine they make one about a fish doctor; aren't we all one? haha!) So, my differential diagnosis: copper leaching from aged water pipes.

Not sure how we can test this without breaking into your house.

What would Fish House MD do?

 

[G H Nelson]

Hi @Myrkk
I would purchase Drop Checker and monitor the Co2 level even though you are not injecting Co2!

If it's green l would be careful when doing water changes and using Prime!
There is alot of compressed Co2 in mains tap water!
Remove any decaying leaf litter use an air pump/stone at night to remove elevated Co2 levels!
Keep us posted on the progress!

 

[Bradders]

I would love to see some pictures of the setup, too.

I think I am with @ElleDee here as an initial food for thought. That sounds like a lot of Prime (overdosing), and a known side-effect of overdosing with Prime is a higher risk of oxygen depletion. The fact that the fish are 'gasping' after a water change shows some correlation, but of course, it does not mean causation. Regardless, that is a problem to resolve. i.e. accurate dosing, and preferably, move away from prime and use something with Sodium Thiosulfate in it - which is harder to overdose on.

Unless the water supply is truly contaminated, then water changes (with correct dosing) should not have such a negative effect. Last weekend, I did a 75% water change (using API tap water conditioner on the replaced water only), and all fish are alive and well. The only aeration going into the new water is the pressure of the tap when filling up a 25L bucket - on top of good surface agitation within the aquarium. Apart from inhabitant stress, water changes of various sizes should not be a problem. An answer here (above changing your water conditioner and getting help checking water contamination) is to aerate your aquarium hugely during the change. In fact, if we can see a picture, it would be great to see how much aeration is occurring with your tank, balanced with plants.

Also, something to think about is that you moved, and since then, fish have been dying after a water change. Does that mean it was fine when you installed and re-set the tank up in your new home, and then subsequent water changes started to see fish losses? Lastly, how did you transfer your filter media during the house move? Was there a chance it dried out or did not receive oxygen to keep the bacteria alive, and you have effectively started over again in a cycle? And in the process of regular water changes, you are never getting cycled?

 

[Hanuman]

I found some chilli rasboras last night, so the fish that did survive varied wildly in size.

5 buckets of water, normal sized buckets, so what, they hold around 7litres. I would say it was a fifth of the tank (200L). The replaced water had enough prime for the 200L tank

I think you may be deoxygenating your water with too much prime. You may not technically be violating Seachem's instructions on the bottle, but you've got a number of things going on that may be working against you that may be resulting in a functional overdose.

You are dosing to your full tank capacity, not to your water volume (and the best practice is to only dose the new water coming in), so you are using more Prime than needed. Your water likely has less chlorine/chloramine than the 1 ppm assumed for the standard dose, so more prime is left over after handling the chlorine to attack other things in the water, including oxygen. Seachem actually recommends using half the standard dose if you have well under that 1 ppm. Lastly, if you haven't been doing regular maintenance, your water might have low oxygen to begin with, so you don't have much of any buffer against excess Prime.

Let's do some math. I'm going to round your bucket up to 8 L and say you are just treating the new 40 L of water at that half dose. That would be 0.5 mL of Prime per water change compared to the 5 mL (or 10 mL for a double dose!) you have been using. A whole order of magnitude different! I think that could result in a catastrophic oxygen depletion and kill fish.

I don't know that this is THE problem, but it's plausible and worth investigating because it would be easy to fix - certainly easier to address than toxic house pipes.

I would say this is it. You have been overdoing it with Prime.
You are basically dosing close to 6x the recommended dose (RMD: 5ml for 200L) for the amount of water your changing!! You should be dosing 0.8ml for the 35L you are changing.

For good measure I would also put an airstone during water change or make sure you have a good surface agitation. Also make sure temperature of the incoming water is the same as the tank temperature.

 

[Bradders]

Just a stab in the dark but so called "old tank syndrome" immediately springs to mind.

I thought about this @Tim Harrison, too. But the ammonia and readings were all very low. Maybe more 'Sick Tank Syndrome' - if not the prime and other aspects.

 

[castle]

I honestly have no idea, but if there was a problem with the pipes you’d be sick too. For that reason alone, I’m not convinced it’s a house thing.

Deoxygenating with prime is a good suggestion too. Maybe do a water change without prime by aging and see what happens?

 

[Tim Harrison]

Here's what I think is happening. From the article I linked above.

The consequence of depleted carbonate in the aquarium water is twofold. Firstly, it can adversely compromise how fish regulate the minerals in their body through osmoregulation. In itself, this can be deadly. Secondly, without the carbonate buffering capacity, the aquarium water pH can drop or fluctuate widely leading to metabolic acidosis in the fish. Either of these situations can cause death, or at the very least cause stress and make the fish more susceptible to disease.

And then water change adds carbonate minerals and causes osmotic shock as suggested by @G H Nelson. Either way in my opinion, the only way to resolve this issue for sure would be to tear the tank down and start again. Like @castle mentions it's unlikely to be water mains related otherwise you be sick too @Myrkk

 

[Hanuman]

Did you see how much prime he was adding? 6x the recommended dose…! If that is not what is causing the fish dying then perhaps he should look into other options but I bet that fixing his dosing will fix his issue specially if the water is already poorly oxygenated.
Also he says that the tank is 7 years old but he replanted it last August so it is unclear if the tank was reset or not. If he did, the old tank syndrom is unlikely.

 

[Surya]

How do you get the water back into the tank? Hosepipe (and if so is it a food safe pipe) or individual buckets?

How do you get the replacement water up to the right temperature? Do you use hot water from the tap, and if so, do you have a combi boiler (fine) or a hot water tank (not fine)?

 

[Bradders]

I bet that fixing his dosing will fix his issue specially if the water is already poorly oxygenated.

I agree.

Some research on Prime has found a few people who have had problems, and some remarks like "The sodium dithionite in Prime and Safe decomposes into sulfur dioxide. In high enough concentrations this gas can be irritating to the gills of fish. In extreme cases and acid water, it can kill the fish. So never use more than a five times concentration of Prime or Safe'.

 

[John q]

Without being the practitioner of doom I'd say the prime suspect isn't prime, the op was loosing fish prior to adding it. See text from original post.

Hi Everyone,
I have a 200L planted tank which is 7yrs old. Moved house last year and every time I did a water change it caused fish to die. They’d be swimming vertically gasping as though they couldn’t get air. pH was 6, hardness was 1, nitrites/nitrite/ammonia all 0. I used to put some bicarb of soda in and it would help a little but it would take a few days for the fish to return to normal.

I therefore stopped doing water changes whilst I tried to figure out the issue.

Last week the heater packed in so the tank had a cold water shock. LFS guy mentioned chloramine (and this forum). I decided to do a small water change yesterday and double dosed the prime. This am all bar 4 of my fish are dead. Nitrites/nitrates/ammonia all 0 and pH 6.

Why are the fish dying? I'm not sure. The standout clue for me is the disparity between tank ph 6, and tap water ph 8.2 average from the report. On a side note with such low conductivity 78 us/cm I find it odd that the tap water ph is so high.

Wish I could offer some constructive advice, I can't other than than suggesting you try a water change with added kh and see if that helps.

 

[richardcunliffe]

if there was a problem with the pipes you’d be sick too.

hot water tank (not fine)?

You're likely not drinking from a hot water tank though, right? So you'd not necessarily notice.

 

[dw1305]

Hi all,

The standout clue for me is the disparity between tank ph 6, and tap water ph 8.2 average from the report. On a side note with such low conductivity 78 us/cm I find it odd that the tap water ph is so high.

It is because of sodium hydroxide (NaOH) injection. Sodium hydroxide is a <"strong base">, so it raises pH, but it doesn't add any buffering.

cheers Darrel