Sterbai Cory with hole in the stomach

[AquaAggie]

I have had 5 corydoras in Quarantine for a month now. They have been treated with 2 rounds of paracleanse. They have been growing well and no longer have swollen stomachs. Went to go get them to move to my main tank and found one looking like the picture below taking its final breaths.
 

obviously transfer is on hold. Remaining 4 look fine swimming around. There are bladder snails, MTS, and mystery snails in the tank with Java fern and hornwort. 
 

Nitrate is 20-30
temp 78
kH ~3
ammonia and nitrite 0
gH 7
pH 7.8

What could cause this?  What do I need treat with again to clear the remainder in quarantine?

 

thanks

 

Edited May 15, 2021 by AquaAggie

[Fish Folk]

2 hours ago, AquaAggie said:

I have had 5 corydoras in Quarantine for a month now. They have been treated with 2 rounds of paracleanse. They have been growing well and no longer have swollen stomachs. Went to go get them to move to my main tank and found one looking like the picture below taking its final breaths.
 

obviously transfer is on hold. Remaining 4 look fine swimming around. There are bladder snails, MTS, and mystery snails in the tank with Java fern and hornwort. 
 

Nitrate is 20-30
temp 78
kH ~3
ammonia and nitrite 0
gH 7
pH 7.8

What could cause this?  What do I need treat with again to clear the remainder in quarantine?

 

thanks

 

Yikes! That’s either something eating out from the inside (worm) or something attacking from the inside. The body lesion is noticeable. Is it possible you’ve got something else attacking it in the QT tank??  

[AquaAggie]

4 minutes ago, Fish Folk said:

Yikes! That’s either something eating out from the inside (worm) or something attacking from the inside. The body lesion is noticeable. Is it possible you’ve got something else attacking it in the QT tank??  

Certainly nothing I’m aware of 😳

[Mmiller2001]

Xenomorph! 

Seriously though, never seen this. Following.

[AquaAggie]

Well it’s been 10 days and the other cories are still alive. Never treated with anything. They are still happily sniffing around the quarantine tank and eating. Was this a one off for one Cory? How much longer should I watch? Should I treat with something?

[Colu]

It's possible it was nematode worms or some other parasites breaking out though the skin it difficult to no sure you could do I proventive treat of paracleanse  to be on the safe side

Edited May 27, 2021 by Colu

[AquaAggie]

13 minutes ago, Colu said:

It's possible it was nematode worms or some other parasites breaking out though the skin it difficult to no sure you could do I proventive treat of paracleanse  to be on the safe side

I had done two round already before this happened. I guess another shouldn’t hurt though?