2x Corys Not Doing Well, Help Please :(

[engenho]

Hi there,
Out of a group of 4, I have 2 cory sterbais not doing well:

cory #1 - recently developed 2 white-ish bumps on both side of the body. Kind of ich but these look a bit swollen. However this guys seems to be great, swims with the other corys, up and down, nibbles all around etc. Seems happy.

cory #2 - no signs of infection on the outside (fins are ok, no ich, etc.). However fins seems to be clamped, stays in same place for a long while whilst the other corys swim happily up and down etc. Seems to have buggly eyes and breathing seems to be heavy compared to others.

Pictures of both corys attached
Let me know if you need videos, I can try and get something over to you...

Water parameters:

• Ammonia – 0
• Nitrite – 0
• Nitrate – less than 5ppm
• Temperature – 27C
• PH – 8.5 >> seems to be high, read more about this below if you feel it could be a root cause of the problems.

Q1 - How should I proceed treating them? I have purchased Seachem ParaGuard, 100 ml
Q2 - I’m conscious corys needing to be in groups of 4+ so is it OK to separate the group having corys alone during the treatment?
Q3 - Should I also medicate the remaining fish in the tank to prevent disease spread?

Regarding PH - I have rocks, medium-heavy planted tank, wood etc. to help bring the PH down although not very successful. From measurements taken on tap water to the water in the tank there’s very little difference. I’m looking to keep stability as advised on YT videos as opposed to use chemicals and eventually crash the PH…

THANKS A LOT FOR YOUR HELP, TIPS, ADVISE.

 

[Byron]

Welcome to TFF.

I'm not going to guess about the "disease" issue as that won't help you at all. Another member may be able to ID the issue and suggest appropriate treatment. Be very careful adding any substance; this does stress the fish, and if it is not going to be effective that is only complicating matters and weakening the fish further.

Do not attempt adjusting the pH down. The pH is part of the chemistry also involving the hardness (GH) and Alkalinity or carbonate hardness (KH). You need to know both of these, and should be able to find that out from your water authority, check their website. The GH is the level of dissolved mineral in the water, and the KH serves to "buffer" the pH, preventing changes. So the higher the KH especially, the less likely the pH will lower. Reducing the GH/KH is necessary in order to lower the pH. Not that I'm recommending this...it is not that simple.

Organic substances (wood, peat, leaves, dissolved organics from the fish) tend to acidify the water and thus lower the pH, but again this is kept in check by the GH and especially KH.

Cories would prefer a sand substrate; that is not causing the issue here, but it is something to recognize as it provides a more natural environment and that helps the fish by avoiding stress. And stress is the prime cause of disease occurring.

Byron.

 

[engenho]

@Biron Thanks a lot for your input. Cory 2 has died. Found it nearly dead the next morning, left for work and when I came back it was gone

Should I proceed medicating the whole tank, just in case the other fish may have something as well?

 

[Byron]

@Biron Thanks a lot for your input. Cory 2 has died. Found it nearly dead the next morning, left for work and when I came back it was gone

Should I proceed medicating the whole tank, just in case the other fish may have something as well?

I do not want to guess as to what this is. Something this quick may show up in the store fish too, I would check with them and if their cories are also showing this, they may credit you for the fish that die. Obviously do not buy more of them until this is resolved.

This also shows the benefit of a quarantine tank for new fish.