whats happening to my fish?

Dec 19, 2009
43
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NW London
#1
I have a 32 gallon tank, which has bee up and running for almost 8 months now. I have had a rash of recent deaths in the tank. 3 platies and a white cloud minnow have died in the last 2 weeks. The platies went first and as they were old I assumed age. I have tested the water and all appears to be fine then the minnow just dies last night. I only have ammonia test strips and was wondering if they were good enough? I change 5 gallons every week, at the time i had 3 corys, 4 platies, 5 tetras, 5 rasboras and 5 white cloud minnows. Aqua advisor said I was changing enough water. Any ideas anyone? wiould I be better off with a liquid test kit to make sure the water is spot on? thanks for the advice.
 

Feb 27, 2009
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#4
15% weekly water changes may not be enough. You should aim to keep the nitrate level at or under 20ppm with ammonia and nitrite zero. A liquid test kit would be helpful to keep track of the water parameters. You may also find that your LFS does free water testing until you get your own kit.
 

lauraf

Superstar Fish
Jan 1, 2010
2,181
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Vancouver, British Columbia
#5
+1 on OrangeCones. A liquid test kit (for ammonia, nitrite and nitrate) is an invaluable investment (pH and alkalinity are bonuses, but usually not the cause of major issues with your tank). Test strips are notoriously unreliable. It will let you know if your water changes are keeping the nitrates at a tolerable level for your fish. Even slightly high nitrates, over time, will stress your fish and can lead to the mysterious deaths we scratch our heads over.
Personally, I change between 25-40% of my water weekly, depending on how much plant pruning I do.
Get your water tested at your lfs, or buy a liquid test kit and test it yourself, and let us know what the readings are. We can try to help you further with that info!
 

Dec 19, 2009
43
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0
NW London
#6
Thanks to you all for the help. Thinking about it , it was after water change so maybe the ph went mad. I have mis stated the size of the tank, I cant get to grips with gallons. Its 110 liters and I change 22 liters a week or 20%. Always thought this would be enough but may increase it to 30% to be sure. Thanks again for the help. Liquid test kit ordered!*PEACE!*
 

breebrry

Small Fish
Jul 3, 2009
43
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0
a town in PA
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#7
if you are changing 20% thats probably enough.. if you change more water than that to frquently you may stress the fish by taking out some of the bacteria the water..

I know of some people before on the forum who were changing to much water and it caused the tank to un-cycle and they had to re-cycle

just some food for thought
 

Feb 27, 2009
4,395
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#8
if you change more water than that to frquently you may stress the fish by taking out some of the bacteria the water..

I know of some people before on the forum who were changing to much water and it caused the tank to un-cycle and they had to re-cycle

just some food for thought
Your tank's beneficial bacteria does not reside in your water column, so doing larger water changes will not cause a tank to 'un-cycle'.

As long as your new water is properly dechlorinated and matches the tank's temperature, there is not a problem with doing large water changes.

If you have NEGLECTED the tank for a long time (not done water changes, are overfeeding, and/or are overstocked), large water changes can cause what is known as 'old tank syndrome.' This is where your fish have become used to such poor conditions, and your pH has becomes very low due to depletion of minerals in the water, that the new water causes a HUGE swing upward toward what is 'normal' for the water's pH. The shock can be deadly and may happen immediately or over a few days.

This happens a lot with folks that just 'top off' evaporated water from their tanks, and seldom actually take tank water out.
 

Last edited:
Feb 27, 2009
4,395
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#10
Just out of curiosity about how long does it take for those conditions to occur?
I have never experienced it as I do not neglect my tanks, but it varies.

It depends on how hard your water is and how high the 'normal' pH is, tank size, stocking levels, and the bacteria action. The more you overfeed or overstock, the more excess food or fish waste must be converted from ammonia to nitrite to nitrate, the more minerals are depleted.
 

lauraf

Superstar Fish
Jan 1, 2010
2,181
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0
Vancouver, British Columbia
#11
Orange, if someone suspects that due to their ongoing negligence, their tank would actually suffer from a sudden large water change, would a nitrate test showing a very, very high level be an indication? Or does one need to test for the mineral levels to determine this?
Obviously, if one is doing proper water changes, this shouldn't even be a question.
 

Feb 27, 2009
4,395
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#12
Orange, if someone suspects that due to their ongoing negligence, their tank would actually suffer from a sudden large water change, would a nitrate test showing a very, very high level be an indication?
It could, but a measure of pH and KH (both tank water and the normal tap water the tank SHOULD have been using for water changes) would be a better indicator.
 

nomisbails

Small Fish
Dec 19, 2009
43
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0
NW London
#13
Thanks for the help, I am still waiting for the test kit to be delivered so I can properly measure all water parameters for water changing. I am just wondering if the ph swing makes such a difference how to controll that? Do you test the tank and then test the change water to balance the two out? I really do my best to keep on top of the water conditions, the feeding etc. I just hope it all works out. Also when changing the water why is it so important to try to keep the water at the same temp? shock? Thanks
 

achase

Large Fish
Feb 1, 2010
765
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British Columbia, Canada
#14
"I have never experienced it as I do not neglect my tanks, but it varies."]I have never experienced it as I do not neglect my tanks, but it varies.
Neither do I and I find the concept of ignoring your tank long enough for "old tank syndrome" to occur bizarre. Do you think it would probably take months?

Also when changing the water why is it so important to try to keep the water at the same temp? shock?
From what I understand that is exactly the reason its important.