Corydoras fins melting/fungused/ I don't know

[Jobro]

Hey there,

bad news. Some of my C. Leucomelas (I had this group for almost 2 years now) are getting some weird greyish stuff on their pectoral fins.

One of them has had this ever since I got him. I didn't notice back when I put them in the tank and since it was only that one and didn't seem to spread onto the others for almost 2 years, I left him swimming. Now for a few weeks I noticed more and more Corys having the same thing going on with their pectoral fins.

It's always only on one pectoral fin, not both.
The fish that had it from the beginning seems to get some on his dorsal now as well.

It's hard to get a good photo of them. It's even hard to catch them.
But somehow I managed to get 2 of them out of the planted tank. I put them in a sperate tank.
I treated both of them in a saltbath today. (1gramm NaCl/liter for 15 minutes)
I hope this can help.

That stuff looks very soft, but it's actually not, I can't remove it physically at all. Hoped it was only some fungus, but with it being so solid, I'm not sure anymore.
I'm really bad with diagnostics of fish diseases. If anybody has seen anything like that before, please let me know.

Left is a newly infected fish. Right is the poor guy that had it for almost 2 years now. His fin has shrunken quite a lot.

I hope anybody recognizes this and can point me to a correct treatment. Thank you.

Sorry pictures are blurry... I really need a good camera.

[Jobro]

Update:

two more pictures:

See the small round dot on the dorsal fin of the right fish.

[dw1305]

Hi all,

See the small round dot on the dorsal fin of the right fish.

Strange, it looks very much like lymphocystis (indovirus), but I don't think that is meant to infect catfish (https://edis.ifas.ufl.edu/fa181).

cheers Darrel

[TwoTankAmin]

According to the link darrel posted, he is correct that it doesn't affect catfish:

Lymphocystis does not affect less advanced orders, including catfish (Order Siluriformes)

It does look like fungal fin rot. I normally treat fungal issues with Mardel's Maroxy. This is a pretty benign med, so if the problem is not fungal, it should not harm anything if you can find it in Germany. mardel is now owned by Fritz Aquatics if that helps..

[TwoTankAmin]

According to the link darrel posted, he is correct that it doesn't affect catfish:

Lymphocystis does not affect less advanced orders, including catfish (Order Siluriformes)

It does look like fungal fin rot. I normally treat fungal issues with Mardel's Maroxy. This is a pretty benign med, so if the problem is not fungal, it should not harm anything if you can find this med in Germany. Mardel is now owned by Fritz Aquatics if that helps. I just sent them an email asking if it is available in Germany. Unfortunately, I am not familiar with most European brands of meds for fish.

One other thing, it is possible to have a fungal and bacterial issue at the same time. So if a fungal med clears up the fluffy stuff but the fins continue to degenerate or do not begin to regrow, you might then consider a bacterial treatment for fin rot. I do know that Maroxy can be use in combination with an antibiotic, I have done this on a few occasions.

[dw1305]

Hi all,

That stuff looks very soft, but it's actually not, I can't remove it physically at all. Hoped it was only some fungus, but with it being so solid, I'm not sure anymore.I

This bit, and the look of the lump in the photo made me think of lymphocystis, but I don't have any other suggestion.

cheers Darrel

[TwoTankAmin]

If its not fungal and catfish don't get Lymphocystis, the only other similar things I can find fall under the category of virus/cancer.

Tumors
Tumors can be caused by a virus or a cancer, but most tumors are genetic. The genetic tumors may be caused from too much hybridization, common amongst professional breeders.
Practically all tumors are untreatable. If the fish is in distress, it should be destroyed.

from http://animal-world.com/encyclo/fresh/i ... 20Diseases

Common Name: Solid tumors of unknown cause
Pathogen/Cause: Not fully understood in fish or man. Many oncoviruses may be suspect in turning off genes involved in tumor suppression. In fish, just as in other animals, may be benign or malignant (cancerous).
Physical Signs: Growing mass of tissue, can occur on almost any part of the body.
Behavioral Signs: Usually not overtly affected unless the tumor is very fast growing internally, or obscures vision, feeding, or swimming.
Potential Treatment: None for most fish. Seek veterinary help for large and/or expensive fish. Surgery often the only cure, though rarely will shrink back on its own.
Other Notes: Not much known about the fish oncology at this time. Watch tumor closely for fast, uneven growth of tumor. If it keeps the fish from feeding and/or swimming, consider euthanasia.

from http://badmanstropicalfish.com/fish_pal ... tml#Tumors

[bekateen]

Thanks. Also, on the link mentioned by Darrel (https://edis.ifas.ufl.edu/fa181), there is a differential diagnosis section that mentions viruses, tumors, etc., which may resemble this.

[Jobro]

I am not sure if it really is fungus. I would expect fungus to be more "fluffy" like TTA wrote. But it's only a little slimy on the surface and the actual tumor/growth seems to be rather hard. Maroxy seems to be not available here. At least not under that name.
I could get other treatments for fungus, but I am not sure if I should use them. Maybe I just have to experiment on those two specimen for the sake of the other corys? (I know that sounds cruel in some way)

If it was "just" a tumor, I think it should not be contagious, right? But this happens to affect at least 4-5 specimen at the same time
Also the fins seem to rot away as well. They get shorter or deformed. Maybe some bacterial problem as a side effect to some other illness?
Lymphocystis seems to be quite fitting here. But if it does not affect catfish? Then it should be out of the question. right?
Maybe some other viral cancer/tumor? As Eric and TTA pointed to allready.

Any Ideas on how to go with this issue?

I really hope it's just a combination of fungus and bacteria... though I have some big doubts about this

[Jobro]

Oh also, big thanks to all of you!
It's so troublesome to make the right decisions in situations like this all by myself.
It's reallly appreciated!

Another edit:

Pygmy cories and other fish seem to be unaffected.

And another input:

Some weeks or rather like 2 months ago I had to take out the HMF to clean it. I also had a canister filter running at that time. But still, maybe I lost a lot of beneficial bacteria in that process?

Anyways, I will remove both Pygmys and Leucomelas from this tank, as it's becoming more and more of a warmwater tank...

[TwoTankAmin]

According to Dr. Tanner, when a matten needs cleaning:

Q: how do rinse Poret® foam sheets?

A: the easiest way is outside in the yard or driveway using a garden hose. Simply bang the sheet flat on the ground several times (Note: I recommend not wearing your best outfit doing this) to shake out the filter sludge, then rinse with the hose; repeat until the water coming out is relatively clean. Don’t overdo it! Sufficient microorganisms will survive this procedure to quickly re-establish the biology of the filter. It does not matter if you use cold or chlorine-treated water! The often repeated notion that this process would kill all the filter organisms is complete nonsense, because the residual chlorine concentration in drinking water is way too low to kill them all.

from http://www.swisstropicals.com/faq/

and

So about 120 min of work per year. The Mattenfilter is left untouched all this time; if you want you can occasionally vacuum the front of the sheet with a hose when changing water. However, in my experience that is not necessary most of the time.

from http://www.swisstropicals.com/library/mattenfilter/

I have never mentioned it, but in my biggest waste producing tanks with mattens, I do the quick surface suck every now and then. I spend maybe 90 seconds at this every few weeks. These are usually the heaviest stocked tanks which also have lots of wood that is slowly breaking down.