Quarantine one corydoras separately?

[Beastije]

Nevermind, the fish just expired
At least it was correct to not return it to the rest

I did a substrate clean again after 3 days at the main tank, another 30% water exchange, will keep an eye on the others...
not sure what happened, might consider taking the stones out in case it was the cause, but no idea how....

 

[DoubleDutch]

Nevermind, the fish just expired
At least it was correct to not return it to the rest

I did a substrate clean again after 3 days at the main tank, another 30% water exchange, will keep an eye on the others...
not sure what happened, might consider taking the stones out in case it was the cause, but no idea how....

Sorry to hear !!!!. In a way it looks weird / strangely shaped to me, but I am not sure what is wrong.

 

[Beastije]

Sorry to hear !!!!. In a way it looks weird / strangely shaped to me, but I am not sure what is wrong.

Right?! Like something is missing from the bottom of the jaw, even the gill was wrongly shaped. I checked the body, no red spots, no blotches, no boils, so at least it should not be the blotch disease.

I found few crumbs of snail shells in the sand that I was sifting today, maybe it cut itself on that, I took it out. Leftovers of shells from the time I had shelldwellers in this tank, I kept most of the same substrate, only increased the sand volume with fresh one.

All the others have full barbs and look good, so fingers crossed they will be ok....

 

[DoubleDutch]

Is the sand shell based or silica?
Could it be it is releasing calcium ?

 

[Beastije]

It is a pool filtration sand, so silica.
The stones may be releasing calcium, sure, but there are not that many of them to affect Kh or anything. I would try to take it out, but not sure how, dont have options and is not easy to manually reach down

 

[DoubleDutch]

It is a pool filtration sand, so silica.
The stones may be releasing calcium, sure, but there are not that many of them to affect Kh or anything. I would try to take it out, but not sure how, dont have options and is not easy to manually reach down

Okay that isn't the issue then !
Some minerals leaking sand can cause issues for Corys cause they are simply on it. Don't think the stones will be the issue either cause it doesn't release from the substrate.