LARGE Goldfish Suddenly Very Sick! (URGENT!)

  • We are currently upgrading MFK. thanks! -neo
Good job Josh, lets see what those water parameters say.
 
haha thanks man, I was waiting for your input here. I'd be a liar if I didn't say a lot of that info was from you helping me with my pickerel's fungus issue.
 
In the main tank: ammonia - 0.25, nitrite - 0, nitrate - 30
I did a 50% water change and will do another tomorrow.

Monster is still alive (I am pleasantly surprised) but is still in the same corner as this morning. I doubt he moved at all all day.
 
A heater? No. The tank is at about 69°F, because that is what the room is at and there is no heater. This is cold for the pleco, I know, but he is moving soon. This is mainly my goldfish tank.

Monster's current hospital tank is at 67-68°F (it has a thermometer).

**Edit: I do have and extra heater that I could put in the hospital if that would be beneficial...
 
My first impression when I saw the photos above was columnaris. In some species especially in cool water, it presents as fungus like tufts, in some cases (primarily in warm water) as a swollen, extended mouth.
I have found, as the disease progresses the fish tends to hover in one area, and may try to eat, but can't.
Raising the temp is the worst thing to do, because the bacteria that causes columnaris reproduces exponentially as temp rises.
It can also easily be transferred tank to tank, by any shared equipment (nets, scrapers), or even hands.
I usually euthanize the heavily infected fish, then thoroughly vacuum the tank, and treat with hydroden peroxide to rid the tank of any residual bacterial populations.
The bacteria thrives in detritus, and there is a theory that high nitrates allows it to more easily infect the fish.
 
Anytime I've experienced columnaris before it has been as a fuzzy-looking infection. I could maybe see how that could describe Monster, but I'm not so sure. I'm not willing to euthanize him since we're unsure, his tankmates are healthy, and he's still going strong(ish).
If I recall correctly, I have had success with Kanaplex (Kanamyacin) treating columnaris in the past. Should I try that?
 
I agree, I would not euthanize unless I was fairly sure.
But just for reference, below is a pic of a fish I had that died of acute columnaris (duck lips form).
 
MonsterFishKeepers.com