ONLY sterbai corydoras infected

[Rocky998]

I'm going to disagree with the diagnosis on the catfish in the picture from the internet. It has two patches of excess mucous, which would suggest external protozoa. It might be poor water quality as well but I don't think it's Columnaris.

The most commonly seen fungus on fish is Saprolegnia, which looks like thin white hairs sticking up from the body. Saprolegnia fungus only gets into damaged tissue and is easily treated with salt. There are no fish in this thread showing Saprolegnia fungal infections.

Regarding Rocky's fish, this is not Columnaris. Columnaris is a fast growing flesh eating bacteria that normally kills fish within 24-48 hours of noticing the symptoms. There are two main forms, one appears on the mouth and spreads over the face and head within 24-48 hours and the fish dies during that time. The other form appears on the back half of the body around and just behind the dorsal fin. Again, the fish dies within 24-48 hours of showing a white patch.
The fact this issue has been going on for about two months says it's not Columnaris. If it was Columnaris, every fish in that tank would have died two months ago.

If it was Columnaris, you would need antibiotics to treat the fish, but it's not so you don't need to worry.

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Cream white or grey patches on the fish are excess mucous caused by something irritating the fish. External protozoan parasites like Costia, Chilodonella and Trichodina cause these symptoms. They can cause the fish to rub on objects (but not always). They take weeks or months to kill a fish, depending on how clean the tank is and how heavily infected the fish is. They generally start out as a pale cream patch on the head or dorsal side of the fish. As the infection gets worse, the fish produces more mucous and the patch can turn white and then grey as it gets worse. The cream, white or grey patch is simply thick mucous. The more mucous the darker the colour. In extreme cases the area around the edge of the infection might start to bleed and look like a red line has been drawn around the patch.

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The dose rates of salt I recommended are generally safe for all freshwater fish and plants. Use 1 heaped tablespoon of rock salt for every 20 liters (5 gallons) of aquarium water. If there's no improvement after 24 hours, add another lot of salt (same dose rate 1 heaped tablespoon for 5 gallons) so there is a total of 2 heaped tablespoons of salt for every 5 gallons of water.

Normally I say add a second dose after 48 hours if there's no improvement, but due to the fish dying now, you should add the second dose sooner.

Keep the salt in there for 2 weeks.

There is no point treating the fish in a hospital tank because the disease (parasites) are in the main display tank. If you treat the fish in a hospital tank and don't treat the main tank, the fish will simply get reinfected when you put them back in the main display. Just add salt to the main tank and treat them all there.

Thank you so much for all this!! It's helping tremendously!

Also, if I double dose on the salt, won't the corydoras be affected by that? I heard that corydoras are among some softwater fish that are more easily affected by salt.

And one more thing, sorry.
When I first add the salt, I'll of course dissolve a small amount in either a half gallon or full gallon of water, but when I go to add it in, in small amounts, how should I go about that? How much at a time over how many minutes/hours? I don't want to put the fish in a shock.

 

[Colin_T]

The fish will be fine with 2 heaped tablespoons of salt per 5 gallons of water. If you were treating livebearers, goldfish or rainbowfish I use 2-4 heaped tablespoons of salt for 5 gallons. The dose rate of 1 to 2 heaped tablespoons is for softwater fishes like tetras, Corydoras and other soft water fishes. It's only for 2 weeks and they will be fine (assuming they haven't gone past the point of no return).

You need a total of 2 heaped tablespoons of salt per 5 gallons of water to kill Costia, Chilodonella and Trichodina.

If you are concerned about using salt, use Malachite Green, but depending on the brand of medication, that should normally be used at half strength for scaleless fish like Corydoras.

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Add the salt water over a 15 minute period.

 

[TwoTankAmin]

@Colin_T
You should read some of the scientific papers on columnaris. Here are some quotes you might find interesting.
Declercq, A.M., Haesebrouck, F., Van den Broeck, W. et al. Columnaris disease in fish: a review with emphasis on bacterium-host interactions. Vet Res 44, 27 (2013). https://doi.org/10.1186/1297-9716-44-27

2.1 Clinical signs, histopathology, ultrastructural features and haematology​

F. columnare causes acute to chronic infections and typically affects the gills, the skin and fins. The clinical manifestation of columnaris disease amongst others is dependent on the virulence of the eliciting strain. In a study of Rucker et al., the strains of low virulence induced slow progressive infections at water temperatures above 21°C and caused massive tissue damage before death occurred [31]. Strains of high virulence caused fulminating infections and killed young salmon (Salmo salar) in 12 to 24 h at 20°C. Ordinarily, these fish did not show gross tissue damage at the time of death [31]. The same was found in a study of Pacha and Ordal [32] and Foscarini [33]. The gross pathology observed in the fish experimentally infected with strains of F. columnare of high virulence was usually very limited. Apparently, death occurred before gross external manifestations of the disease appeared. However, some of the last fish to die did show macroscopically visible signs [34]. Besides the virulence of the strain being a determinant factor, in coldwater and temperate fish, age also seems to have an important impact on the severity of the clinical signs. In young fish, the disease develops acutely and mostly damages the gills (Figure 1). In adults, the disease may adopt an acute, subacute or chronic course. When the disease course is acute or subacute in adult fish, yellowish areas of necrotic tissue can appear in the gills ultimately resulting in complete gill destruction (Figure 2) [1, 32, 35].

In chronic cases, it takes longer before gill damage appears and skin lesions may develop as well [1, 32, 35]. On the body, small lesions start as areas of pale discolorations of the skin, which usually are surrounded by a zone with a distinct reddish tinge. This mostly begins at the base of the dorsal fin. Fin deterioration then occurs, starting from the lesion at the base of the fin and progressing to the outer edge, the opposite to normal finrot. The lesions then begin extending laterally from their common location at the base of the dorsal fin to encircle the fish resembling a “saddle-back” (Figure 3). The disease therefore is referred to as “saddle-back disease” [1, 32, 36]. Finrot is also often present [1, 37].

You can read the whole paper here https://link.springer.com/article/10.1186/1297-9716-44-27#Sec6

This one is interesting because of the use of chloramine,

Altinok, I., 2004. Toxicity and therapeutic effects of chloramine-T for treating Flavobacterium columnare infection of goldfish. Aquaculture, 239(1-4), pp.47-56.Abstract

A clinical field trial was conducted to evaluate the efficacy of aqueous chloramine-T to control mortality of goldfish (Carassius auratus) fingerlings infected with Flavobacterium columnare. In addition, the acute toxicity of chloramine-T to goldfish was determined in glass aquaria under static conditions. Chloramine-T concentrations in the toxicity test ranged from 5.0 to 40 mg/l. The concentration of chloramine-T that killed 50% of the goldfish within 24 h (24-h LC50) was estimated as 24.3±0.6 mg/l (95% confidence limits). Two days after exposing goldfish to F. columnare, fish were treated with chloramine-T ranging from 0 to 25 mg/l. None of the uninfected control fish died, and all deaths occurred between 3 and 11 days after exposure to F. columnare. Mortality of the untreated control (0 mg/l chloramine-T) group was 70% while survival of fish was significantly increased with increasing chloramine-T concentration up to 15 mg/l chloramine-T. When the concentration of chloramine-T was increased from 15 to 20 or 25 mg/l, survival of fish decreased. F. columnare was isolated from skin and gills of all fish that died during the experiments but was not isolated from survivors 21 days after exposure to bacteria. Results indicate that 15 mg/l chloramine-T can be used to treat columnaris disease in C. auratus under the experimental conditions of this study.

full paper here https://www.sciencedirect.com/science/article/abs/pii/S0044848604002984

There is a ton of research that has been done on the disease. You can spend days reading papers on it. The one thing you will see is that there are strains which are deadly and kill fast and other strains are chronic and can take a long time to kill. The most virulent strains tend to kill befoer any symptoms appear. The more chronic and less virulent strains will show symptoms, will progress slowly and may not kill for some time.

What is clear is that this disease is not a one size fits all sort of thing. Their are a variety of factors involved. Different groups are found in water of different temperature. The age of the infected fish may matter as well. But not ever case of columnaris is going to kill in 24-48 hours for sure.

As for treating this disease have a look here for "About 8,170 results"
https://scholar.google.com/scholar?hl=en&as_sdt=0,33&q=flavobacterium+columnare+treatment

 

[CassCats]

Protozoan infections do not eat the flesh away like that, especially on an armored fish.

This is bacterial and yes there are a few strains of columnaris and not all are quick. Some are slow and agonizing.

 

[fishorama]

I agree with 2tank & CassCats, there are 2 forms of columnaris, the fast & the slow. With the fast form, it kills very fast, in just a few days. You can almost never catch it soon enough to treat it. But the slow form is treatable with kanamycin (Kanacin) if treated long enough. Salt may help, but it is not the corys best option; they're salt sensitive. Since you are in the US, I'd go with Kanamycin. Change a good amount of water before each retreatment & keep it up for a while, say 2 weeks.

Good luck

 

[GaryE]

In your seeking advice, you're getting caught between knowledgeable voices. I lean Columnaris, and here is why.

I bought some cardinals a few years ago. Within a couple of weeks, they showed columnaris, after QT was (too quickly - only 2 weeks) was done. I changed how I quarantine after that. The symptoms were textbook. But the progression wasn't. Over 3 months, the cardinals all died. They lingered a long time if I didn't euthanize. No other fish in their tank were ever affected, including cardinals from a previous import.

We call this infection columnaris, after one member of the Flavibacter family, but there are relatives who do similar damage. My assumption after losing all those cardinals was that I had seen a Flavibacter infection of some sort, and however the fish had contracted it, it had stayed with them and didn't spread. It was unfortunately difficult to tell old cardinals from new, and I removed the fish at the first signs. After trying to save the first few (when I learned this was a slow Flavibacter type), I euthanized them. But I counted, and lost exactly the number of new ones I'd bought.

Sound familiar? Slow progression, unstoppable, and stayed within one species.

Against that? I've never seen a Flavibacter infection on a Cory, and the armour changes the look of everything. The deformity on the corpse looks Flavibacter to me. The skin film looks like a protozoan infection. As lightweight as this sounds, I think your fish have "something weird" that is probably bacterial.

I don't think you have a cycled hospital tank to treat them in. If you did, I'd treat for protozoans because they are easier to kill, and if it didn't work, would aim for, well, in my country, black market antibiotics or stoicism. I think they're doomed at this point.

Many plants will be harmed by salt - others not so much.

 

[Rocky998]

Alright. I thank you all for your advice, but it is overwhelming to have a lot of different opinions on a time sensitive situation. I will be starting salt treatment today to see how it goes.
If it doesn't start working, I'll stop it and then try something else. Maybe then move to the bacterial side of things and get antibiotic meds

 

[GaryE]

None of us has a laboratory, which is what we'd need for what we say to be more valuable than opinions...

Pick a course. Follow it. It may be wrong. If it is after a time, try another.

We know about diseases, but we don't know what disease your fish are suffering from. That much is clear in the thread. All the people answering have seen a lot and tried to learn more, but we're making educated guesses from photos.

 

[Rocky998]

I don't know if my air pump will work yet, so how should I go about keeping the water oxygenated?

 

[Rocky998]

@GaryE @Colin_T
How should I go about adding the salt to the tank?
I understand it's 2 tbsp per 5 gallons for me, but I know it should be done slowly by dissolving it in a gallon of water.
But how much do I add over the course of how much time? (If that question makes sense? Lol)

And should I add in the actual FULL dose for 40g? I only ask because there lots of sand, wood, the filters, plants, and rocks... So that causes a ton of water displacement...

 

[Rocky998]

I'll also hopefully be getting catappa leaves to add during the time the salt is in the water

 

[Rocky998]

Here's a clearer photo of the corydora. This one IS MINE

 

[GaryE]

I don't want to complicate matters, but personally, I never use salt for Corys. It can be a very useful chemical for a lot of situations, but in my experience, Corys do poorly with it. Colin has seen different things, so his advice goes in that direction.

I don't know anything that's going to solve what you see there.

 

[Rocky998]

I don't want to complicate matters, but personally, I never use salt for Corys. It can be a very useful chemical for a lot of situations, but in my experience, Corys do poorly with it. Colin has seen different things, so his advice goes in that direction.

I don't know anything that's going to solve what you see there.

Well crud lol. I'm about to put salt in the tank. I'm very overwhelmed rn.
Should I just go the medication route then?
I really don't want to hurt my corydoras further...

If they do react badly to the salt, do I just do a large water change in would that put them into a shock?

 

[Rocky998]

I don't want to get so overwhelmed it triggers a meltdown for me (I am autistic in case you didn't know. Some situations, especially those that have to do with special interests, can trigger them easier than other things for me. I've been doing really good at not having a bad meltdown, so I'm trying to remain stable with all these overwhelming things)

Just thought I should say that cause it's very hard to get a ton of input from a ton of different sides that say different things on a time sensitive matter.
And lots of input is not good for me right now as I'm already overwhelmed