# Other Aquarium Forums > Fish Care, Nutrition and Water Management >  Why is my Corydoras always at the water surface?

## NinjaFly

Hi all corydoras lovers/expert out there!

I have a question on a particular weird behaviour of my corydoras.
Wonder if anyone out there have similar behaviour.

My peppered cories and Sterbais has been always at the surface layer of my water sucking in lots of air thus creating lots of bubbling sounds.

My other corydoras like Corydoreas Aeneus, Corydoras Concolor, Corydoras Habrosus, Corydoras Pandas, Corydoras Pygmaeus, Corydoras Trilineatus and the rest all stays below.

Any advice?

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## fishboy

Do they exhibit any signs of stress i.e. rapid gill movement etc? Cories do occasionally pop to the surface to gulp some air. If they dun exhibit stress and are eating and scanning for food, they should be fine. Maybe they were banished by the rest :Smile:  [ :Grin: ]

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## CoryDorus

The two Sodalis Corys I have also exhibit same sympton but not the rest, especially at night I can hear it's sucking sounds. I think .. i think hor ... don't bomb me ... their gills probably deteroriated before due to poor condition.

And even after the condition has been Righted, damage is done. :Sad:  

Having say that, they normally swim in mid-water among the taller plants unlike other corys at the bottom. And is really pleasing to look at, this couple swimming gently together in mid-water criss-crossing each other. Cannot describe the romantic feeling. 

[: :Smile: ] [: :Smile: ] [: :Smile: ]

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## NinjaFly

Not too sure for the peppered cories.. But my Sterbai seems quite healthy just that it loves to suck air at the surface thus creating lots of bubbling noises.

Recently, I had a peppered cory that seems to be sick and when I looked closly at its gills, it is a bit redish. Anyway, the two peppered cories has been 1.4 yrs old alreadya.. Dunno if it is due to age.

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## ek

NinjaFly:
u may want to try salt treatment. The last time one of my cory also has reddish gills and it was always hiding and not eating. After the salt treatment it was back to normal within 2 days.

Actually cory are quite hardy fishes.

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## philtre

hi ek,

care to share what's your salt treatment like for your cories? like how much salt/ procedure etc?

thanks a lot in advance!

cheers

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## ek

Just in case u misunderstood, I was not referring to those salt bath for serious case.

What i did is simply dissolve about 1 tsp of salt into a cup of warm water and then pour into my planted tank (100L).

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## DEA

i've never seen my cories do this other than the first day
maybe they're just exploring
but since yours are quite old, it might be that the oxygen level in your water is too low for that particular species

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## NinjaFly

Hmm ... Just noticed that my Albino Cories is at the surface blowing bubbles too...

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## DEA

albino ah
that one i think is for fun
the albino cories are among the hardiest i've seen
the sole survivor from my first days of fish keeping is an albino aeneus
keep an eye out for them and see how?

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## NinjaFly

Once thing I noticed. Last time when I do feed on my fish, my corydoras will be busy finding the leftover food on the gravel. But recently, most of my corydoras aren't really interested in them. *sign* .. dunno if it's the heavy bioload that cause them to grasp more air.... :Sad:

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## Nature

joke time
is going to give birth hehehe
hope u all dun bomb me  :Smile:

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## zac08

Possible... I have a heavy bio-load too.... and now with both internal filters running, I think the water temp is raised slightly too..... thus no choice, have to aerate more.... But I still see them going to the surface pretty often, even at night....

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## coryfav

I've seen and heard of corys going to the water surface for atmospheric air. But it's the &amp;quot;sucking in lots of air thus creating lots of bubbling sounds&amp;quot; that puzzles me.

Mine normally just splash some water onto my face and go directly back into the bottom.

Bubbling sounds? Lack of oxygen in the water? :Smile:

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## NinjaFly

:Sad:  sob  :Sad:  ... 1 peppered cory and one c. juli had died. Observed that both had quite red gills then. Not too sure of what had happened ..

I am pumping in air now and see if the condition gets better.

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## Nature

HaiZ..bro dun too sad....!!!
hope i can help but really dun know what happen....!!!
i will help to find out throught encyclopedia

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## NinjaFly

Here is one of the pictures that I have captured. Here you can see 4 corydoras at the surface.

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## loupgarou

hmm: my albino cory is also one of the cory survivors of tank of doom 1 and 2 episodes..

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## joe

Ninjafly, something is obviously very wrong with the water or gravel. My 50+ cories are 99% of the time at the bottom and only comes up once a while for air.

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## CoryDorus

The Picture doesn't seems right. 
 :Sad:   :Sad:   :Sad:

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## PeterGwee

Clearly lack of O2 or some gill infection...

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## BFG

Ninjafly, the pics u provide shows 1 of the cory is actually upside down! The other fishes looks to be swimming properly. It looks like the cories are the only one affected. Did u introduce any wild species?

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## NinjaFly

What are the things needed to find out what's wrong?

My cories have been behaving well only until recently when I started to notice this weird behaviour. 

But apparently all my other fish are ok.

I have Cardinal Tetra, Guppies, Rasboras (Harlequin, glowlight and blue eye). My pearl Gouramis seems to be appearing abit unwell too.. have been resting and not really swimming well for weeks but apparently nothing happened. 

Also, only my C. Panda, Albinoes, Sterbais, Julis are behaving in that way. While my Kuhi loaches and C Aeneus had their body colours fading off.[ :Knockout: ] 

My other cories like Pymgaes, Habrosus, Metae, Cconcolour, Narcissus, Brevirostris and a few other species are ok.

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## BFG

Why not isolating the sick fishes into another tank or a large pail?

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## coryfav

C. aeneus albino is one of the hardiest cory that I've ever come across. If they start showing negative signs...  :Sad:  

Ninjafly, time to isolate those corys into another tank with enough oxygen.  :Wink:

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## DEA

check for rotting material in the tank
also, clean out your filter and wash the filter media
not kidding

especially with the high temperatures in the tank, oxygen levels will already have dropped
if something is consuming oxygen as it rots, it'll drop even more
add an airstone if you see more discomfort

hth

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## ek

Let's summarise the immediate task to be done:
1)Treat the sick fishes with salt using a spare tank or pail and with airstone. Make sure to add water conditioner to the spare tank b4 adding fishes.
2)Change water (50%?) for the 4ft tank and look for dead fishes/shrimps and rotting material.
3)Clean the filter.

Hope that your fishes will be well soon.

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## NinjaFly

Well, some findings here...

PH and NO2/NO3 levels seems ok. But recently I noticed quite a number of leaves starts rotting off. One of my Nurphar Japonica had completely rot off leaving only the rhizome while I have some vals leaves rotting off eversince I rooted up some...

My cories are sucking a lot of air causing lots of bubbling noise. Have been changing water 50% every week now. Hope to see some improvement.

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## coryfav

Just a thought...

If water condition is causing corys to hang around near the surface and sucking in atmospheric air, won't a 10% water-change daily (for the first few days, at least), be better than to wait for a week before changing 50%?

May not sound good, having to do those exercises daily, but what do you think?  :Smile:  

I'm doing that for one of my tanks now, which saw some cory-deaths at one-cory-a-day late last week and during the weekend. Ever since I switched to 10% daily, so far so good. Touch wood!  :Smug:

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## PeterGwee

NinjaFly..did you see any bubbles coming out from the substrate when you uprooted those rotting vals? Anerboic substrate releasing toxics causing death to some of your fishes? Just a thought though..might be wrong.

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## BFG

PeterGwee could be rite! The cories could have swam into an anerobic area. That's explain why only the cories are affected. The kuhli could be affected too.Your cories lung could have been damaged while inhaling the gas. 

If u have a satay stick or equivalent, just poke the substrate 2 see where the bubbles are.

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## NinjaFly

*Coryfav*: 
Will follow your advice by doing frequent water daily. Will a pail of water for a 4ft tank be enough?

*DEA*:
My tank temperature is always at about 26-28 except for recent hot days where the temperature reaches 29 with the help of 2 DC fans. Does that consider as high temperatures? BTW, I am already adding a air tube in to help in the oxygen level.

*ek*:
The problem is that I am not sure if the cories is considered as sick or not. They only exhibit those weird/unnatural behaviour but overall, they still looked quite healthy to me (at least now).

*PeterGwee*:
I have tried stiring some gravel but no bubbles seen. But I do see bubbles floating up last time when I uprooted my Nurphar Japonica for giveaway. But I have been very careful in not breaking the roots. BTW, does bubbles in the gravel means that the substrate is Anaerobic? 

Oh yeah, a question. Will a anaerobic substrate causes the fish water to foul or smell awful? Coz my water don't smell.

BTW, thank you all. I really appreciate your feedback/advice.. :Wink:

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## philtre

don't know if it's a coincidence or what it's supposed to mean ... but seems that your bottom dwellers are in trouble.

kuhli loaches and cories .... might wanna do a detail inspection to see what the cause could be?

hope things get better soon.

regards

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## coryfav

Ninjafly, if you're refering to the standard pails that some households use for laundry, that amount should be around there. Depends - you'll have to look at your tank's condition, maybe every 2 days, if not daily? 

For the amount (of est 10%), maybe you can take out some water into that pail and estimate from the water level? But again, I think you've more plants and gravel in your tank, than mine... I use the white plastic containers from Ikea which are somewhat rectangular, so I can more or less calculate the volume from there.  :Wink:  

Got to observe the tank and trial-and-error from there, cos each tank is different and may reacte differently too. 

Meanwhile, I also think you should look into the gravel.  :Smile:

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## ek

Ninjafly,

Cories are not known to stay near the surface of the water like aro does. Even if they want grap some air they will do it very secretly (actually abit coward) and in a split of a second they will come down to the bottom again, look for food or resting(dreaming) on the tank bottom. So if they keep staying near the surface this is really odd.

Why not net one out and see how it behave a few days later?

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## PeterGwee

Ninjafly...did the cories still stay near the water surface when you added the airpump? Are your plants growing well and pearling at the end of the day? If the airpump were to work, you might just need a powerhead to circulate the water in the tank more to improve oxygenation.

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## joe

> ----------------
> On 5/23/2003 12:49:38 PM 
> 
> Why not net one out for salt treatment and see how it behave a few days later? 
> ----------------


Not advisable. Cory catfish are not suited for intense salt treatment. I've 70+ cories and have never ever done that to them.

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## DEA

> ----------------
> On 5/23/2003 10:58:49 PM 
> 
> 
> 
> 
> 
> ----------------
> On 5/23/2003 12:49:38 PM 
> ...


i have
no losses
just don't add the salt in the solid form
dissolve the salt and add it to the water very slowly
the myth probably comes from incidents where people simply dumped the salt water into the tank and the cories swam right into it
this happens with pandas, instant death

i however don't recommend taking out the fish to treat with salt
salt doesn't cure everything
in this case, it's more than likely there's something wrong with the water conditions, in which case salt does zip
i'd suggest carrying on with the water changes, cleaning out the filter if you haven't already, and try siphoning the muck off the gravel

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## ek

I'm not referring to salt bath or intense salt treatment (see my earlier post). The reason for netting out for treatment is cos there are already two dead and it may take some time for the water to get back to normal condition.

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## NinjaFly

> ----------------
> The reason for netting out for treatment is cos there are already two dead and it may take some time for the water to get back to normal condition. 
> ----------------


Well, so far so good. There hasn't been anymore casualties. As I have at least 50% of my gravel densely covered with E. Tenellus, I find it quite difficult to disturb and siphon the gravel.The rest is either blocked by wood or small plants.

Anyway, I have been doing 10% water change daily and I am still monitoring the fish. Maybe I will try out this salt treatment. BTW, a question. Right now, my fish are more or less &amp;quot;100% freshwater&amp;quot;, by adding salt in, will that cause discomfort to them and turning them to &amp;quot;brackish&amp;quot;? And those salts treatment that you people are refering to, are they the aquariam salts or normal table salts?

*PeterGwee*: My plants have been growing well except that there isn't much bubbling now as my bioload is quite heavy. As for the circulation of the water for better oxygenation, I think with my 2 filter output at each end, I think it should be sufficient. [: :Smile: ]

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## DEA

> ----------------
> On 5/24/2003 6:44:17 PM 
> 
> The reason for netting out for treatment is 
> 
> ----------------


basically, when fish are sick, netting them out usually stresses them to the point where they can't fight off the infection anymore
not a really good idea to net fish out for any reason
even when the water conditions are bad, it's a much better idea to rectify them than to move them to a new location, which is a stop gap measure

salt will stress the fish, definitely
no point in using the salt as a general panacea if you don't know what's wrong
usually makes things worse
tried carbon? might be dissolved organics in the water screwing things up
and have you cleaned out your filter yet?

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