Mystery lesion on rasbora

[jgoldberg]

Hi there,

Hoping to get a second opinion on my Espy's rasbora (aka porkchop rasbora), which seems to have developed a mysterious lesion/growth overnight. The lesion is at the base of the tail and appears as a white protrusion when viewed in profile. I would say it's growing internally and protruding through the scales. I've pulled the fish into a quarantine tank and am preparing to treat.

I had another individual in this school of fish manifest similar symptoms in November. In the previous episode, I quarantined the fish and treated with a few remedies (Maracyn 1 and 2, maybe Ich-X, aquarium salt), but the lesions grew and spread, and the fish succumbed after a few weeks (in a quarantine tub). I have some pictures of the more advanced disease from the previous case if that's useful.

The symptoms don't seem to match any of the usual suspects so I'm a bit at a loss as to what I'm dealing with and what might be effective. The only thing that seems to fit is mycobacteriosis, which 😬😬😬. I'm not terribly keen to trash the fish and plants and nuke everything with lysol, especially not across the multiple potentially cross-contaminated tanks – I do my best to keep things clean and separated, but I'm realistic about the limits in a home setting.

The sick fish was in a 40 Gallon breeder in a school of 8, along with a couple of cories, 5 otos, a bristlenose and 2 dwarf flag cichlids. All fish save the one rasbora look healthy and normal. The tank has been running for 6-8 months and has a pretty well established plant community. No fish have been added (or removed) since December. Water parameters have been stable for the duration of operation.

Temp 23-24˚C/74-76˚ F

GH ~180 ppm

KH ~80 ppm

pH 7.6-7.8

Ammonia 0

Nitrite 0

Nitrate ~20

No significant changes have occurred to the tank recently, save adding a new Anubias, which was bleach dipped and quarantined for a week.

Looking forward to outside input. Happy to provide additional information as required. Thank you.

[xXInkedPhoenixX]

Hmm, I'm wondering if it's Columnaris. @Colu? Look like that to you?

[jgoldberg]

I think I started Jungle Fizz + Kanaplex immediately prior to death of the first fish. Like I started the treatment and the fish was dead the following morning. The disease was fairly advanced at that point, so it was a bit of relief if I'm perfectly honest.

[jgoldberg]

I went ahead and dug out the photos of the first round of battling this infection/disease. Might be helpful or not.

Edited April 18 by jgoldberg
Readability

[Colu]

The fact that it took a couple of weeks for the Frist fish to die means it's less likely to columnaris with the lesion the one thing that jumps to mind is neon tetra disease it can infect Rasboras danios barbs guppies angelfish you often get lesion on the muscle tissue  I can't rule out a bacterial infections at this point what I would suggest is to treat with a combination of kanaplex and jungal fungus clear fizz tabs containing nitrofurazone following this treatment plan it effective for more severe bacterial infections if it's not  improving after the Frist course give us an updated

Edited April 23 by Colu

[xXInkedPhoenixX]

Yes, I'm leaning towards this is Columnaris and what I would treat the tank for. This is a notoriously hard/stubborn disease to treat and the symptoms are at times perplexing as it can be an internal and external disease. Possibly by the time you've seen the lesions it's advanced. It seems to be living in your tank looking for its next compromised victim which is why  I'd probably bomb the whole tank with Columnaris meds. That's just me, maybe there are others with insight who will post. 

[jgoldberg]

Thanks @Colu and @xXInkedPhoenixX!

I will proceed with Jungle Fungus and Kanaplex and probably just treat the infected fish in quarantine as a start. I'lll need to do a water change in my 10 G QT for the treatment, but it's cycled and empty.

What's the safety of this treatment for my planted tank? I'm open to treating the display tank, but want to confirm that this is the cure before committing.

Neon Tetra Disease seems like a possibility as well. I actually had a group of 6 neons in the tank for a month or so last fall (approx. September 2022) and then relocated them to another tank. All are still alive, although in less than perfect condition. They have white growths near the mouth, like warts – I'm almost certain it's not cotton mouth/saproglenia. A couple have some fin/scale damage, which seemed like it might just be some intra-school aggression. They've had these symptoms for months without any apparent change, so I had just left them be. Perhaps, I should have been more proactive. I can share pictures of those guys if helpful...

Edited April 18 by jgoldberg
typo

[Colu]

Sound like neon tetra disease in your other fish that spreads by your fish eating dead infected fish they become infected with to many pleistophora for the immune system to handle leading to neon tetra disease best treatment for neon tetra disease is to quarantine any fish showing symptoms so they don't die in the main tank and get eaten infecting more fish the treatment plan I recommended is very effective at treating columnaris and other server bacterial infections it can take to two full courses of treatment back to back in severe cases if they are showing no signs of improvement after two full courses of treatment your more than likely dealing with neon tetra disease kanaplex can effect some types of plants I haven't had any issues when using it in planted tanks in the past @jgoldberg

Edited April 18 by Colu

[jgoldberg]

I’ve just dosed day 5 of @Colu’s treatment plan. If I am doing a second round of the plan, would that begin tomorrow (day 6 from first dose) or the following day? I believe I have seen other posts where 2 50% water changes are recommended in between. I assume that would apply here, correct?
 

The rasbora seems to be doing well in spite of being in a bare tank by itself. I think there may have been some improvement but I haven’t evaluated the situation too closely since I expected to complete at least one round of meds and the tint of the water from nitrofuranzone makes seeing the lesion/growth difficult.

[Colu]

On 4/23/2023 at 5:10 AM, jgoldberg said:

I’ve just dosed day 5 of @Colu’s treatment plan. If I am doing a second round of the plan, would that begin tomorrow (day 6 from first dose) or the following day? I believe I have seen other posts where 2 50% water changes are recommended in between. I assume that would apply here, correct?
 

The rasbora seems to be doing well in spite of being in a bare tank by itself. I think there may have been some improvement but I haven’t evaluated the situation too closely since I expected to complete at least one round of meds and the tint of the water from nitrofuranzone makes seeing the lesion/growth difficult.

What you can do is two 50% water changes or one 50% water change and run active carbon for 24hr before starting a second course of treatment 

[jgoldberg]

Thanks @Colu! I did two 50% water changes and started a second round of treatment.

I took a better look at the damaged tissue after the water changes. I'm not sure I observed much improvement of the situation. The growth is still protruding from the base of the tail and is now bloody after the minimal/gentle handling between the display and quarantine tanks. However, the situation doesn't appear much worse either. There's been no spread of the disease to other areas of the body (as I observed in the previous case). So I guess the initial returns are inconclusive and I'll hope that the situation resolves itself by day 10. Hoping this isn't NTD, but not much I can do about that at this point.