# Fish gasping at water surface after water change



## mr_convitbau (Jan 7, 2009)

I am raising cardinal tetras and discus in my 45 gallon tank. The discus are the newcomers.

I have been doing 50% WC every week. The water temperature was at 78F before the arrival of the discus. The cardinals were perfectly fine after each WC at 78F.

Lately, I added 6 discus. I raised my temperature to around 85F. After a few hours following the WC at 85F, all the fish (cardinals and discus) gasp at the surface. I have lost some of the fish due to this problem. The survivors however return to normal the next morning, meaning they breathe and swim normally without gasping at the surface.
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Are there any thoughts on this?*

IMO, I guess the fish gasp at the surface because there is not enough oxygen in the water. When I did WC at 78F, the water is cooler than at 85F. I guess the hoter the water is, the less concentrated the oxygen level becomes in water since gas evaporate more easily at higher temp. The phenomenon is like when we boil water, there are more and more bubbles coming out as the temp goes higher and higher.

There are still a lot of tiny bubbles after each WC. I guess at 78F, some of those bubbles dissolve back into the water, making it more concentrated with oxygen. However, at 85F, there are not many of them doing so. The bubbles at this temp just flow up to the water surface and evaporate.
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Am I thinking right? Any other thoughts are more than welcome. Please also give a suggestion for solving the problem. *


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## TAB (Feb 7, 2009)

yes, as the water getts warm the less O2 it will hold. 85 is a bit warm for most discus. 

I always leave a air stone in my wc water.


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## Six (May 29, 2006)

I'm not sure if you're adjusting the temp back and forth- it seems like you may be from your post. If you want 80 degree water and they've been at lower temps, let them acclimate to the norm for a few weeks, raise it a bit, repeat. Fluctuations will definitely cause issues and possible immune system breakdown (and possible disease issues). Just take it slow and give them time to acclimate. 

And TAB's right on about the O2. 
GL!


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## ErioLover (Apr 30, 2009)

I agree with above. I like to use slightly cooler water than the tank for changes.


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## mats808 (May 7, 2008)

Mr. Convitbau,

How are you getting the 85 degree water for your water changes? I assume that you are heating it in some kind of a container prior to putting it in your tank. If this is true and you suspect low oxygen levels just put an airstone in the container while you are heating the water. Also you could lower the temp a couple of degrees. The discus should be fine at 83ish.


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## niko (Jan 28, 2004)

My bet is that the water company is playing their usual tricks. Every so often the tap water's parameters change. I'm talking substances that you can't test for. I import rare fish and water changes are an important part of the quarantine. Every so often a species of fish that had no issue with the water changes would act strange after changing the water. It happen to me about 3 days ago once again. And keep in mind that I don't change a lot (maybe 30% tops so the impact is minimal). I filter the tap water through a big carbon filter AND dechlorinate with ClorameX. 

I have come to believe that such issues are some factors in the water, not necessarily chlorine/chloramine but something else. Adding an activated carbon filter in the tank usually solves the problem, but nevertheless the whole experience is very frustrating. 

Just last night I visited a discus breeder that has abandoned the in-line activated carbon filtration for his tap water. He now uses a big water storage tank and dechlorinates with only ChlorameX. The water sits in the water storage tank for at least 1 day. If you are dechlorinating in your tank (adding water + putting dechlorinator at the same time ) then I don't have much to say - that's a common and bad practice and you need to change that.

--Nikolay


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## niko (Jan 28, 2004)

Also read Jane's post here:
http://www.aquaticplantcentral.com/.../62559-water-change-kills-shrimp-doesn-t.html

Basically the tap water is not always consistent - that's what my point is.

--Nikolay


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## mr_convitbau (Jan 7, 2009)

mats808 said:


> Mr. Convitbau,
> 
> How are you getting the 85 degree water for your water changes? I assume that you are heating it in some kind of a container prior to putting it in your tank. If this is true and you suspect low oxygen levels just put an airstone in the container while you are heating the water. Also you could lower the temp a couple of degrees. The discus should be fine at 83ish.


Yes, I used water that was previously heated for WC. The reason I keep my discus at 85F is because they are juveniles. Folks from simplydiscus.com suggest that high temp to increase metabolism in young discus so that they can maximize their growth.

I think my initial guess of oxygen depletion after my WC is correct so far. The last time when my fish gasped for air at the water surface, I tried to increase surface movement by pointing my filter outlet upward. That helped a lot.

When my discus become "adults," 83F as you suggested will be perfect for them.


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## mr_convitbau (Jan 7, 2009)

niko said:


> Just last night I visited a discus breeder that has abandoned the in-line activated carbon filtration for his tap water. He now uses a big water storage tank and dechlorinates with only ChlorameX. The water sits in the water storage tank for at least 1 day. If you are dechlorinating in your tank (adding water + putting dechlorinator at the same time ) then I don't have much to say - that's a common and bad practice and you need to change that.


I wish I could store water in a separate tank and let it dechlorinate for at least 1 day as you suggested. My problem is I am living in an apartment, so there is no more room for such a big container . I will definitely follow that method for WC when I move to a bigger house (after graduating from college and find a job, I guess ).


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## Heiko Bleher (Mar 11, 2007)

Hi,

this is Heiko Bleher and I can only say follow Niko's advice.

I just came back from lectures in London, Ontario, Canada and decorating biotope aquariums 8look at my website under Bleher's Biotopes for discus biotopes and others. And the same thing happened to two breeders in Ontario: They changed water and their discus became back (some lost as well).

You must remember, discus come from almost stagnent habitats and there the water movement is little. And it is really not needed to change so much water (but definitely add what evaporates).

Naturally you MUST not take the water EVER from your tap or shortly after it is heated. Important is that the water has been storaged and an air stone in it all the time. And keep it with peat moos if it is for discus also for a few days like this BEFORE you ad it to your aquarium. You can NEVER trust the water from the pipe.

Advice from one who does it all his live and collects them,

always

Heiko Bleher
www.aquaptess-bleher.com
www.aqua-aquapress.com


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## Nevermore (Mar 26, 2007)

6 discus should not be in a 45 g tank.


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