Help Corydoras Pygmaeus Transition Issues


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2 years

The sick Cory (He even looks sad in the picture)


The healthy Corys( I can’t even get a good pic they are so active)


What is the water volume of the tank?
10 gallon qt tank

How long has the tank been running?
Bout a month fully cycled

Does it have a filter?
Thirty gal sponge

Does it have a heater?

What is the water temperature?

What is the entire stocking of this tank? (Please list all fish and inverts.)
9 Pygmy Cories and
1 cherry shrimp (survived a friends gouramI tank so he just hangs out here now)

How often do you change the water?
whenever nitrates rise to high(depends on the fish in qt)

How much of the water do you change?

What do you use to treat your water?prime and stabilty(just for this tank as a sort of fishless cycling experiment)

Do you vacuum the substrate or just the water?
Substrate and water

*Parameters - Very Important
Did you cycle your tank before adding fish?
What do you use to test the water?

ApI test kit

What are your parameters? We need to know the exact numbers, not just “fine” or “safe”.


How often do you feed your fish?
1daily (light flake very small broken up price of shrimp pellet) I can’t stress how light my first feeding was.

Illness & Symptoms
How long have you had this fish?
1 day

How long ago did you first notice these symptoms?
Immeadiatley when introduced

In a few words, can you explain the symptoms?
No movement no appetite, hard to tell on the respiration’s as it is sooooooo tiny of a fish but it goes between very slow and very fast but I can barely see the gills

Have you started any treatment for the illness?

Tried a partial water change, to bring the nitrates down to around 5, they were only like 10 before the water change.

Was your fish physically ill or injured upon purchase?
All the other Cories are swimming about this one doesn’t move at all unless I touch it,

How has its behavior and appearance changed, if at all?
It is a darker color than all the others

Explain your emergency situation in detail. (Please give a clear explanation of what is going on, include details from the beginning of the illness leading up to now)

I got the Pygmy corydoras at the local fish store.
I understand they are sensitive to water as they are very small but the other 8 schooled(shoaled if you prefer) right up and have non stop been cleaning the tank and just generally being an adorable little school of fish, this 1 little fella has just sat at the bottom the whole time and only moves when he/she is disturbed. It has been a full 24 hours and no change.

No visible differences between him and the other fish besides he is just a little darker and his activity level

I tried hand feeding and he swam into my hand and laid there, I brought him to the top quickly as they often swim up and gulp for air and then placed my hand mid tank still holding the fish, he swam up took a gulp of air on his own and settled at the bottom of the tank and seemed to be a lighter color emphasis on SEEMED to be as I just want to provide all the information on things I have done / tried and their results. The water change didn’t help either(probably stressed him more) but it was all I could think of.

Is it time to give up hope on this little guy? He seems like a fighter so if he just needs time I want to give him that but if he’s in pain or slowly starving to death I don’t want to prolong that. And or if he has something that could spread to my seemingly fit as a fiddle corys I don’t want that either. I’ll post pics of what I can and I tried to answer all the questions in the emergency template I just didn’t think food would matter as he won’t move or eat anyway he doesn’t seem to have any physical differences besides a slight dark coloring, (no bloating, no fungus) although he is so tiny maybe I just can’t see it? Any and all help would be better advice the the guy at the lfs who said and I quote “catfish are just lazy and wait for food to come to them like that sometimes”

I know these guys can be sensitive but it’s my understanding that if it had a problem with the new water or tank change from the store to my home it would just die by now not tough it out for a full day as it has.


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4 years
Maybe he had some sort of problem with the acclimation? My oto catfish were all fine except one when I first acclimated them, the others were going crazy when I first introduced them, and one was just sitting there, kind of in shock. I treated the tank with my beloved prime and tetra tablets, and he was fine after about fifteen minutes. How did you acclimate the fish? I find that drip acclimation is the best for very sensitive fish, and I did not do that with my otos.
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2 years
I didn’t do it with the bag that he was in because I didn’t read about it until this happened unfortunately, but as I said it’s been a whole day and he just sits there breathing but not moving as if in shock like you describe. Usually when my fish do this because of acclimation they are belly up within hours, the next morning at the latest. Although it is not something that happens to me often so I can’t say for certain if taking this long is normal

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