Mystery Deaths After Water Change In 35L Tank

[Rak9378]

Hey Daize.  Sorry to hear about your problem!  I have been doing a lot of reading trying to educate myself on water chemistry.  While I am by no means an expert, I am wondering if your fish are going through osmotic shock.  Have you measured parameters such as GH, KH and TDS?  Do you know what is causing the pH to increase? From what I have read when there is a big enough difference in the TDS (total dissolved solids) from the tap vs TDS in the tank it can cause a fish to have issues regulating its internal salt/water balance (i.e. osmoregulation).  Done slowly most fish can acclimate and adjust (for example drip acclimating a new fish).  But when the change is rapid (like during a water change) the fish's regulatory system is not able to acclimate fast enough.  This can lead to a number of issues including death.  There are many who believe that pH shock is not the problem it is made out to be except for extreme ranges and certain sensitive fish. 
 
All of this being said, I'm not sure why it would happen in your 35l and not your 64l assuming all variables are equal.  Is there anything you do different with the 64l?  Different substrate? Dosing of minerals? etc?
 
Again I want to emphasize that I am by no means an expert!!  I almost didn't post this response because I don't want to send you down a wrong path.  But I figured if I put enough warnings that I only know enough to be dangerous it would be ok

  Hopefully if anything I have said is wrong someone will correct me.  At the very least I gave you something to spend the day researching

 
 
 
 

 

[daizeUK]

Hey Rak, my tap water here is very hard (300mg/L CaCO3 according to my water authority). The water in the tanks is also hard according to my Tetra strip tests which give a result of 15dH. I don't think hardness can be the problem because it is consistently hard - there is nothing in the tanks that might drastically change hardness.

The difference in pH from tap to tank is simply dissolved CO2 in the water supply. After a few hours in the tank the CO2 diffuses out and the pH reverts to its natural level accordingly, just as it would if left in a bucket overnight. I think this is fairly common and nothing to worry about.

I am still stumped about why I only see the distressed behaviour in my 35L tank and not my bigger tanks. The best lead I've got to go on so far is that I might have been overdosing my Prime dechlorinator, but I would expect to see the same symptoms in my other tanks since I overdose them just as much! One possible reason I thought of is that both the bigger tanks have a lot of plants and plants are good at absorbing toxic substances.

Yesterday I performed 50% water changes on my 64L and 120L tanks using buckets treated with the recommended single dose of Prime in an attempt to minimise the amount of dechlorinator I added. I hoped that this might help to reset any build-up of Prime in my tanks. Then I shut down my 35L tank of death and transferred the remaining survivors to the 64L where they seem to be happier.

In total I had 3 deaths out of 10 juveniles, plus a fourth who was on the brink of death when I transferred her to the 64L. She was lying on her side at the surface and swimming very erratically in jerky movements. Surprisingly she's still alive this morning and valiantly trying to swim although something keeps bringing her back to the surface. Last night she was spinning in circles trying to stay upright, poor thing. I was on the verge of euthanasing her but I wanted to see if she had any chance of recovery after moving tanks. At least she seems to have righted herself this morning but she must be exhausted.

What might cause a fish to swim like that? Does it sound consistent with some kind of chemical poisoning?

 

[coolie]

Here is the concentrated dechlorinator I spoke about, it does exactly what it says on the tin: http/www.ebay.co.uk/itm/Concentrated-Aquarium-Tap-Water-Dechlorinator-Fish-Chlorine-Chloramine-Remover-/300871346778?pt=UK_Pet_Supplies_Fish&hash=item460d546a5a

 

[Rak9378]

Hey Rak, my tap water here is very hard (300mg/L CaCO3 according to my water authority). The water in the tanks is also hard according to my Tetra strip tests which give a result of 15dH. I don't think hardness can be the problem because it is consistently hard - there is nothing in the tanks that might drastically change hardness.

 
Hi Daize.  While GH and TDS do measure some of the same minerals in the water (namely calcium and magnesium), TDS is much more comprehensive....it basically captures everything that is dissolved in water.  This inludes sodium, chemical substances, hard minderals, biocarbonates, etc.  So while your GH out of your tap may be the same as the tank that may not necessarily be the case for TDS. 
 

I am still stumped about why I only see the distressed behaviour in my 35L tank and not my bigger tanks. The best lead I've got to go on so far is that I might have been overdosing my Prime dechlorinator, but I would expect to see the same symptoms in my other tanks since I overdose them just as much! One possible reason I thought of is that both the bigger tanks have a lot of plants and plants are good at absorbing toxic substances.

Yesterday I performed 50% water changes on my 64L and 120L tanks using buckets treated with the recommended single dose of Prime in an attempt to minimise the amount of dechlorinator I added. I hoped that this might help to reset any build-up of Prime in my tanks. Then I shut down my 35L tank of death and transferred the remaining survivors to the 64L where they seem to be happier.
 

 
From what I have read it would take very excessive overdosing for Prime to have any negative effects.  The negative effect being reduced oxygen.  This assumes that there aren't any other reducing agents being used at the same time.  This is why it is not recommended to dose both Prime and Excel as TTA discussed above.  But a double dose of Prime used on its own should not have resulted in the fish deaths you were experiencing.  Prime also does not build up over time in the tank.  It is used up within 48 hours and therefore there is no need to reset anything....its not like ferts.  Here are some links to a Seachem support forum that discuss Prime...
 
http/www.seachem.com/support/forums/showthread.php?t=2803
 
http/www.seachem.com/support/forums/showthread.php?t=3983
 

In total I had 3 deaths out of 10 juveniles, plus a fourth who was on the brink of death when I transferred her to the 64L. She was lying on her side at the surface and swimming very erratically in jerky movements. Surprisingly she's still alive this morning and valiantly trying to swim although something keeps bringing her back to the surface. Last night she was spinning in circles trying to stay upright, poor thing. I was on the verge of euthanasing her but I wanted to see if she had any chance of recovery after moving tanks. At least she seems to have righted herself this morning but she must be exhausted.

What might cause a fish to swim like that? Does it sound consistent with some kind of chemical poisoning?

 
The jerky movements could be due to a loss of equilibrium...a sign of osmotic stress/shock.  As is inertness.  Have you noticed any other symptoms at all?  Clamped fins, changes in color?  In the fish that died did you notice any redness near the gills?  Rapid breathing is also a symptom but I know you already said you didn't observe that. 

 

[daizeUK]

Here is the concentrated dechlorinator I spoke about, it does exactly what it says on the tin: http/www.ebay.co.uk/itm/Concentrated-Aquarium-Tap-Water-Dechlorinator-Fish-Chlorine-Chloramine-Remover-/300871346778?pt=UK_Pet_Supplies_Fish&hash=item460d546a5a

API Tap Water Conditioner still works out as better value
http/www.amazon.co.uk/API-Tap-Water-Conditioner-473ml/dp/B004LO9KSY/ref=sr_1_1?ie=UTF8&qid=1392975635&sr=8-1&keywords=api+tap+water+conditioner

Yours treats 14000 litres for £4.95 + £0.68 postage = 2486 litres per £
API treats 35,810 litres for £6.65 + £2.05 delivery = 4116 litres per £

Can anyone beat the API stuff?!
 

From what I have read it would take very excessive overdosing for Prime to have any negative effects.  The negative effect being reduced oxygen.  This assumes that there aren't any other reducing agents being used at the same time.  This is why it is not recommended to dose both Prime and Excel as TTA discussed above.  But a double dose of Prime used on its own should not have resulted in the fish deaths you were experiencing.  Prime also does not build up over time in the tank.  It is used up within 48 hours and therefore there is no need to reset anything....its not like ferts.  Here are some links to a Seachem support forum that discuss Prime...

The jerky movements could be due to a loss of equilibrium...a sign of osmotic stress/shock.  As is inertness.  Have you noticed any other symptoms at all?  Clamped fins, changes in color?  In the fish that died did you notice any redness near the gills?  Rapid breathing is also a symptom but I know you already said you didn't observe that.

Awesome Rak thanks! Always good to know this stuff. I am dubious that the Prime was really at fault but I just have nothing else to go on...

There is something else, actually. I noticed an abnormal build-up of white solids in that tank a couple of weeks previously. It looked a bit like excess limescale, mainly on the sides of the glass and it also covered the moss ball that I had in there. I blamed a couple of fake 'white rock' ornaments that I'd put in the tank from Pets at Home so I took them out and forgot about them. Let me find a picture of them.

[sharedmedia=core:attachments:72921]

Okay so I took those white rocks out a couple of weeks ago, cleared the white dust off the glass and did a 50% WC all on the 3rd Feb. Their next water change was 12 days later, 50% on the 15th Feb. Fish started dying a couple of days later on the 17th, 18th, 19th.

Maybe you're right Rak and those fake rocks increased the TDS? Strange that nothing especially bad happened on the 3rd Feb though. I did a GH test at the time to check hardness levels and noticed nothing unusual but like it's been said already, the test strips are probably useless!

The symptoms were clamped fins, inactivity and huddling together, loss of colour and an unhealthy sheen with some scales looking unnaturally shiny. No red gills or rapid breathing that I noticed. I don't think it was anything to do with oxygen because they were huddling at the bottom of the tank as well as the top.

They're all back to normal again now in the 64L tank. They are eating and grazing on plants and behaving normally. A couple of them still look very pale. There's no sign of the fish who lost her equilibrium and was swimming erratically at the surface, I'm not 100% sure but I think she may have recovered.

 

[Rak9378]

Awesome Rak thanks! Always good to know this stuff. I am dubious that the Prime was really at fault but I just have nothing else to go on...

 

No problem!  Glad I was able to help! 
 

 
There is something else, actually. I noticed an abnormal build-up of white solids in that tank a couple of weeks previously. It looked a bit like excess limescale, mainly on the sides of the glass and it also covered the moss ball that I had in there. I blamed a couple of fake 'white rock' ornaments that I'd put in the tank from Pets at Home so I took them out and forgot about them. Let me find a picture of them.



Okay so I took those white rocks out a couple of weeks ago, cleared the white dust off the glass and did a 50% WC all on the 3rd Feb. Their next water change was 12 days later, 50% on the 15th Feb. Fish started dying a couple of days later on the 17th, 18th, 19th.

Maybe you're right Rak and those fake rocks increased the TDS? Strange that nothing especially bad happened on the 3rd Feb though. I did a GH test at the time to check hardness levels and noticed nothing unusual but like it's been said already, the test strips are probably useless!

The symptoms were clamped fins, inactivity and huddling together, loss of colour and an unhealthy sheen with some scales looking unnaturally shiny. No red gills or rapid breathing that I noticed. I don't think it was anything to do with oxygen because they were huddling at the bottom of the tank as well as the top.

They're all back to normal again now in the 64L tank. They are eating and grazing on plants and behaving normally. A couple of them still look very pale. There's no sign of the fish who lost her equilibrium and was swimming erratically at the surface, I'm not 100% sure but I think she may have recovered.
 

 
Hmm, that is interesting.  Is there a chance the decorations weren't aquarium safe?  I suppose if they were leeching something into the aquarium it would have an impact on TDS.  Keep in mind GH wouldn't have captured whatever it was that was in the water so I'm not surprised that GH didn't show anything.  Those symptoms can all be attributed to osmotic stress but I guess they could be attributd to a number of other things too.  Would have been really interesting to get the TDS reading from that tank.  But I guess the important thing is the remaining fish are safe and behaving normally.  Glad to hear that one fish recovered!! 

 

[daizeUK]

I don't think I will ever trust fake ornaments again. Not that I liked them much anyway but I thought I could keep them for use in quick temporary tank setups. Now I just don't trust them.

One thing I don't understand, if the problem was down to osmotic shock then surely moving the fish to the 64L would have made them worse not better?

 

[TwoTankAmin]

A couple of things- daize are you sure that white stuff is fake. It looks like it could either be dead coral or tufa. Both would raise hardness in the water. Tufa is used by rift lake keepers to help the hardness and pH up.
 
Rak- drip acclimation is mostly useless for acclimating fw fish in terms of osmotic shock. If you read the research into this you will see that acclimation to really different conditions takes days to well over a week. Many of the physiological changes inside the fish do not manifest until 5 to 6 days into the acclimation. However, research indicates that the addition of a small amount of salt to acclimation water when fish arrive will help a great deal.
 
Most studies I have seen involving acclimating fish to different conditions (besides temperature) seem to involve an acclimation period of 7-14 days.
 

Gill membrane remodeling with soft-water acclimation in zebrafish (Danio rerio)
You can link to the full study form the abstract.
 
If interested, I can point you to more acclimation studies where they takes days to acclimate and detail what and when physiological change take place.
 
 
 

 

[daizeUK]

A couple of things- daize are you sure that white stuff is fake. It looks like it could either be dead coral or tufa.

I'm sure it's fake - I have two of them absolutely identical. Probably a resin cast. The paint is starting to wear off in places.
Found the link from where I bought it: http/www.petsathome.com/shop/en/pets/fish-tank-ornaments--plants-and-gravel/coral-natural-rock-ornament?pageSize=45#

 

[KirkyArcher]

I had one of those very same resin "rocks" in my 32 litre, Never had any issues that you are going through with it!

 

[Rak9378]

One thing I don't understand, if the problem was down to osmotic shock then surely moving the fish to the 64L would have made them worse not better?

 
This is just speculation but if I had to guess I would say that once you did the water change the level of TDS was reduced enough to cause osmotic stress.  The fish that lived were eventually able to acclimate to the lower levels and return to normal behavior.  Because you removed the source of the problem, the TDS level in the tank did not rise again.  When you moved the fish to the 64l they didn't show any signs of stress because the TDS level was similar to the 34l.  Again pure speculation without knowing for sure if the ornament was the source and what the actual levels were. 
 

A couple of things- daize are you sure that white stuff is fake. It looks like it could either be dead coral or tufa. Both would raise hardness in the water. Tufa is used by rift lake keepers to help the hardness and pH up.
 
Rak- drip acclimation is mostly useless for acclimating fw fish in terms of osmotic shock. If you read the research into this you will see that acclimation to really different conditions takes days to well over a week. Many of the physiological changes inside the fish do not manifest until 5 to 6 days into the acclimation. However, research indicates that the addition of a small amount of salt to acclimation water when fish arrive will help a great deal.
 
Most studies I have seen involving acclimating fish to different conditions (besides temperature) seem to involve an acclimation period of 7-14 days.
 
Gill membrane remodeling with soft-water acclimation in zebrafish (Danio rerio)
You can link to the full study form the abstract.
 
If interested, I can point you to more acclimation studies where they takes days to acclimate and detail what and when physiological change take place.
 
 
 

 
Thanks for the info TTA.  See..I wasn't lying when I said I know enough to be dangerous. 

  I would absolutely be interested in reading up on those studies. 

 

[daizeUK]

I had one of those very same resin "rocks" in my 32 litre, Never had any issues that you are going through with it!

Maybe there's something in my water supply that reacts with it ??? Or maybe it got chemically altered by high ammonia levels during my first fishless cycle. So confusing!