Is this columnaris?

[echl5723]

5 of the 7 sterbai cory in my discus tank have some sort of sickness, and I can't figure out what it is. The fishes are not bothered by it (this has been going on for over a month with no fatalities), but I can tell that it started with a couple cory and it spread.
They are now in hospital tank (it has been 2 weeks), I'm afraid it may spread to my discus.
There are lumps/sores on the fish body, they are whitish, and the fishes also have rugged and split fins/tails (not sure if that was due to the sickness or german blue ram picking on them, but they have not been healing). They are eating and somewhat acting normal (hard to tell since they are not in the usual tank).
I thought It looked like Columnaris; but the usual medicines aren't working. I have done:
1. 7 day full dose of seachem paraguard before moving them to hospital tank
2. 3-doses round of seachem kanaplex (in water, not fed)
3. just finished 5-doses round of mardel maracyn

The hospital is a 10g tank with hob filter with cycled media, 7.6 pH, 20% water change every other day, water temperature is 80F.
I have observed no improvements. Right now I'm giving the fishes a break from the antibiotics.
Any suggestion what this sickness is and what medicine to try next?

thanks

 

[pip walters]

It could be, but also could be parasite infection such as chilodonella or costia.

To eliminate chilodonella, try a salt dip. 20g per litre for up to 15 minutes or until the fish shows adverse effects.... which will probably be sooner than 15 minutes with corydoras. Remove to clean water as soon as any signs of stress show. Try one fish at a time, just in case - individual fish can react differently to salt treatment.

I would also treat the main tank with a bactericide.

 

[Delapool]

It could be, but also could be parasite infection such as chilodonella or costia.

To eliminate chilodonella, try a salt dip. 20g per litre for up to 15 minutes or until the fish shows adverse effects.... which will probably be sooner than 15 minutes with corydoras. Remove to clean water as soon as any signs of stress show. Try one fish at a time, just in case - individual fish can react differently to salt treatment.

I would also treat the main tank with a bactericide.

Is there any way to tell at all? Or could one lead to the other can I ask?

 

[pip walters]

Without a microscope to view scrapes from the affected fish, it is difficult to know for sure, which is why I suggested the treatments above. Yes, damage from parasitic infection can become infected with columnaris and other bacteria.

 

[Delapool]

Yes, it narks me that it can be a combination of things and everything seems to be described as white to greyish-white. Thinking I might get myself an early holiday present of a book on fish diseases so I have some photos to compare.

 

[foster53]

It could be, but also could be parasite infection such as chilodonella or costia.

To eliminate chilodonella, try a salt dip. 20g per litre for up to 15 minutes or until the fish shows adverse effects.... which will probably be sooner than 15 minutes with corydoras. Remove to clean water as soon as any signs of stress show. Try one fish at a time, just in case - individual fish can react differently to salt treatment.

I would also treat the main tank with a bactericide.

These are cories!!! Catfish & salt don't mix.

 

[Delapool]

These are cories!!! Catfish & salt don't mix.

I've wondered on that. Some info says done it and was ok, others say not?

I've used a salt dose at 1/3 to normal and fish looked fine and not having problems. The b/n catfish was getting to 4 inches though so a decent size.

 

[pip walters]

These are cories!!! Catfish & salt don't mix.

I have suggested a short term dip here,. I have used this for many species from catfish to elephant noses, with no problems.

Check these out - they live in the sea

Saltwater Aquarium Fish for Marine Aquariums: Coral Catfish

 

[Delapool]

I have suggested a short term dip here,. I have used this for many species from catfish to elephant noses, with no problems.

Check these out - they live in the sea

Saltwater Aquarium Fish for Marine Aquariums: Coral Catfish

Can I ask if you vary the dip strength for different fish at all or by anything else (eg young fish). Or if anything else has an impact?

I thought neons were sensitive as well but they were fine at a normal dose. I even stepped the dose up gradually just in case. I'm guessing that my water is a little bit harder than natural environment for them so it wasn't too big a step.

 

[foster53]

I have suggested a short term dip here,. I have used this for many species from catfish to elephant noses, with no problems.

Check these out - they live in the sea

Saltwater Aquarium Fish for Marine Aquariums: Coral Catfish

Those are marine fish. Cories are freshwater fish. Have to compare apples to apples.

 

[pip walters]

Can I ask if you vary the dip strength for different fish at all or by anything else (eg young fish). Or if anything else has an impact?

I thought neons were sensitive as well but they were fine at a normal dose. I even stepped the dose up gradually just in case. I'm guessing that my water is a little bit harder than natural environment for them so it wasn't too big a step.

Yes, always start with the lower dose and increase the dip time. If the fish see little problem for up to 15 minutes, then -if needed - increase the dose strength next time.

I suggested 20g per litre as I have used this for corys before, but you can start with 15g per litre. It does vary with species.

 

[pip walters]

Those are marine fish. Cories are freshwater fish. Have to compare apples to apples.

Yeah, sorry I was being pedantic as you said catfish and salt don't mix.

As I said, the treatment is a very short term dip. Many fish considered salt intolerant will tolerate a short term dip when removed to freshwater afterwords.

Salt intolerence normally refers to long term salinity of the water.