Slow developing illness with possible columnaris lesion

[Coryluv]

This concerns an X-Ray pristella tetra. My tank has been set up for about a year and I've had this fish about 10.5 months. It was part of a group of 7 pristellas.

It has lived peacefully in my DT for its entire tenure with me until a recent move to my QT. My DT is:

29 gallons
76 degrees
0 nitrites
0 ammonia
7.8 pH
10 ppm nitrate
Planted and fertilized with Seachem root tabs, Flourish comprehensive, flourish excel, and API leaf zone
Fluval 206 filter (no carbon)
2 T Fluval peat in filter
2 mystery snails
2 rummy nose tetras
5 peppered corys
7 (now 6) X-Ray pristella tetras

The fish in question has always eaten well and would school with the other tetras but during the day has always hung out alone behind the plants for the most part.

Two weeks ago, I noticed a dark "smudge" on the fish's left side, about 3/8 in. across, that appeared to be mostly internal, but also external. I researched and came across ammonia as a possible culprit for blackened skin. Since my tests always came back 0 and I noticed no other signs and no other affected fish, I took a wait and see attitude.

About 4 days ago, on this pristella, I noticed a lesion on the upper right side towards the head, but well behind the gill. It was raised, yellowish with pinkish, possibly bloody edge. It was about 1/8 in. across. In a day it grew to 1/4 inch x 1/8 inch, and turned cottony white (fine, short cottony threads). I was able to net the fish and remove it to my 10 gal QT.

I suspect a strain of columnaris as the cause of the white lesion. I began treating the fish with Maracyn 2 in my QT.

QT 10 gallon
0 ammonia
0 nitrite
5 ppm nitrate
7.8 pH
76 degrees F
Aquaclear 30 HOB filter (no carbon)

The good news is that the lesion is healing quickly and as of tonight, is only a faint, nearly imperceptible line.

The black is another matter. There definitely is a patch of blackened skin/scales. The blackening is minimal and there are no obvious lesions, bumps, or red streaks, etc. The fins all look very healthy. The internal looking black remains (it's really hard to tell exactly what is internal and what is external).

The affected scales are not all black, but rather seem kind of edged in black and still retain their reflective sheen. There are no lumps, bumps or other external deformations. This black area neither grows nor shrinks since it appeared.

If pristellas weren't semi transparent I would not be able to see the internal black. I can only see it because pristellas are so "see through".

The fish seems to swim, breathe, and eat normally.

I'm going to continue the 5 day course of Maracyn 2. I have some Furan 2 on hand, and I've ordered some Kanaplex. I plan to move on to those when the course of Maracyn 2 is over and it is removed with water changes and carbon, unless someone says a reason not to.

My other fishes in my DT have to date shown no sign of whatever this is.

Anyone have any ideas? Has anyone seen anything like this?

I've been reading everything about columnaris and myxobacteriosis is which some say is a form of black columnaris. I've gone though all the fish disease information I can find and nothing really fits what I'm seeing on the black.

I think if the black were internal columnaris the fish would already be dead or nearly so, but I don't know for sure.

This sure has me stumped.

 

[Coryluv]

I just got a photo. Like I said most of this black is internal.

 

[Matt68005]

Youve done everything right with the minocycline. It is strange, a lesion from Columnaris or Tetrahyemea (parasite) would definately be tan brown not black. Wierd.

 

[Coryluv]

Thanks for the input! This is another case of spending $25 to try to save a $1 (on sale) fish, but since it is in QT and not endangering the others, I dearly want to try to cure it. As long as it appears comfortable and is eating I'll do what I can for it.

 

[Delapool]

Youve done everything right with the minocycline. It is strange, a lesion from Columnaris or Tetrahyemea (parasite) would definately be tan brown not black. Wierd.

Almost the same I think - the ones I've seen are streaks of red and black on a swollen patch. Not like that at all.

 

[Coryluv]

Almost the same I think - the ones I've seen are streaks of red and black on a swollen patch. Not like that at all.

Thanks. I've been Googling like crazy and can't find anything that looks or sounds like what I see, though from its response the the white fuzzy lesion was a gram negative bacteria (perhaps an opportunistic secondary infection).

All I see is this internal and external black. I can see some internal black on the other side of the fish, too, but not as much as this side. I can't see any deformations or tumors at this time.

I'll update if and when something changes.

 

[Coryluv]

I said that I'd update whe something changed. Well today I have to give up. I've completed three rounds of three different antibiotics, including the very strong Furan 2 - Kanaplex combination. Everytime I finish a course the lesions come back. I give up. I can't cure this. This morning after completing another round of meds, my fish has another big pink lesion forming. The internal black has never gone away, though the surface black did. The internal black never got any better. The lesions seem to grow from the inside to the outside. Kanaplex treats internally, too, so I thought that would fix it. Whatever it is, the battle is lost. I'm getting ready to euthanize the fish before the latest lesion gets any worse. I'm writing this as I'm getting the icy water ready. It is hard when a fish just dies, but this is harder. This was a good little fish and I'll miss her.

 

[Delapool]

Sad news. Very, very sad to lose a fighter like that.

I'm posting below on extra ideas to put them out there but have found little success once a fish is badly infected.

So antibiotics +/- tri sulpha with lower temps and salt in tank water is what I have tried.

H2O2 has also been used in one case on here.

This is where I go off the deep end but I have speculated that driving the ph down to say 6.5 might take it out of the preference range of bacteria which on some reading seemed to like above 7. Never tried this.

 

[Coryluv]

Thanks Delapool. I'm glad you put those ideas out there for others. I'll never know what this was but I feel like all I was doing was treating secondary infections. I was never able to cure whatever turned the fish black internally. Because pristellas are pretty transparent I was able to see things that normally would have been unseen.

I didn't attempt a necropsy, I just don't have the equipment or wherewithal; but after the fact I was able to see the fish looked slightly swollen on one side as well as the previously mentioned symptoms.

I spent the afternoon breaking down the tank and bleaching everything. Just waiting for it all to thoroughly dry now.

 

[Delapool]

Sad news. Heck, I'm sorry we couldn't be of more help. Appreciate the post letting us know.

It does make me wonder sometimes as the cost of the meds here far exceeds the cost of the fish. But I chalk it up to experience, a duty of care that I can do and sometimes there is a great win. Probably stupid really.

 

[Coryluv]

Never stupid. We have a duty to do the best we can for our finned friends. I know I did the best I could, but there is always that nagging feeling that if only...