# Corydoras are easily stressed



## AkCrimson (Dec 17, 2009)

I think it's an acclimation thing. I've got corys in my 55. I'm always goofing with that tank and when I need to move a plant or something and one of the corys is near it, he just sits there and chills while I am working right next to him.

Sorry you lost some fish


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## blackandyellow (Jul 1, 2009)

CrazyCory said:


> Learned it the hard way. I was pulling some plants out from my 10 gallon cory tank which I have not touched for about 2 years, and got these little guys stressed. After that, I lost 4 fishes in 7 days. :icon_sad:


What exactly do you mean with "not touched for about 2 years"? No water changes, no trimming of plants, nothing at all? Did you change the water or was it significantly different from the water in the tank?

Some cories are very shy but I wouldn´t expect them to die from just pulling plants out of the tank


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## pinkertd (Jun 17, 2007)

Sorry to hear that. I doubt it was from stress unless you have sterbai. Sterbai emit a toxin from glands behind their gills when stressed and can commit suicide that way.
If you haven't disturbed the substrate in 2 years then suddenly pull up plant roots while fish are in the tank, at a minimum they'll get sick, or they'll get sick enough to die. Too many nasties stirred up that they inhale. Sorry for your loss. icon_sad:


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## CrazyCory (Apr 29, 2009)

I have a very heavily planted 10 gallon tank. most of the space is filled by java moss and flame moss. I do weekly water changes, and cleaning the HOB filter, but I did not touch the bottom of the tank where they live for about 2 years. I think they like it that way. My corydoras Panda bred quite a few times in the tank. I've been keeping corydoras for about 10 years, never had this problem before. I think if I stir up the bottom of the tank once in a while so that they got used to this kind of stress the disaster can be prevented. The proof is, I put in several corydoras pygmaeus into the tank about a month ago. Nothing happened to them. 



blackandyellow said:


> What exactly do you mean with "not touched for about 2 years"? No water changes, no trimming of plants, nothing at all? Did you change the water or was it significantly different from the water in the tank?
> 
> Some cories are very shy but I wouldn´t expect them to die from just pulling plants out of the tank


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## pinkertd (Jun 17, 2007)

While the water column may be clean for them to live and breed happily in your tank, you upset the water column severely by releasing all that old mulm out of the substrate. For the fish, it was like suddenly putting them into the waste sewer. It's quite possible that by bringing that mulm into the water column that it also cause an ammonia and/or nitrite spike. Undisturbed mulm in the substrate will not harm the fish unless there's a lot of uneaten food in it, then you're going to have higher nitrate in the water column on a regular basis. Fish being kept in churned up substrate mulm will make them sick. They'll pull some of that dirt in through their gills, their skin and eyes are exposed to it while they are swimming in it. It does make them very sick.


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## CrazyCory (Apr 29, 2009)

I agree. Stirring up the mulm is a bad idea.


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## mumushummus (Sep 16, 2009)

yeah thats right ! When I do that I regret it after... always came with a lost of fish sad but true...


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## h2osanity (Sep 19, 2008)

That's very interesting.
I just removed all of my 3" eco complete substrate, sieved it for coarser pebbles and MTS and then returned it to the tank with all the livestock in situ. (too many to catch and too stressful to catch everything but I hated the quartz pebbles that rose to the surface after capping with EC)

Critters include 6 Metae corys and 6 pygmys, rasboras, bolivian rams, cherry and amano shrimp. I kept a bunch of floater plants in there for comfort and did some water changes to reduce the cloudiness. Tank has been running 2 years with constant maintenance and some vacuuming periodically.

No losses, not a lot of stress. Rams were trying to spawn that night...


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## pinkertd (Jun 17, 2007)

h2osanity said:


> did some water changes to reduce the cloudiness.


The water changes make all the difference in the world. I've rescaped my 72G which has very deep gravel, right with the discus, cories and tetras in the tank. But I do constant water changes the whole time I'm uprooting the plants. And hold my breath, it's still a bit of a gamble. The better condition the fish are in, the easier they will fare through the rescape.


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