Nagging tetra problem

[QTOFFER]

I have a generally healthy 58 gal community tank populated by zebra danios, tetras, and corys (see my sig below). Water parameters are good (pH 6.8, 0 ppm NH3, 0 ppm NO2, 10 ppm NO3). Temp is kept at 80 - 82oF. I do 40% water changes weekly.

When I first set up the tank in Nov, all the tetras got ich. I cleared that up with heat treatment alone. Since then, I have waging an ongoing battle with a columnaris-like infection that only seems to affect my four serpae tetras.

One serpae, in particular, is not as vibrantly colored as the other serpaes and he has a hazy greyish-white complexion. When I bought him, he was deep orange. In addition, his tailfin is slightly damaged but his other fins are perfect. He behaves and eats normally, but occassionally he gets one or two (less tham 1 mm) raised white bumps on his side. There are no red streaks or signs of anchorworm. His breathing is normal and he does not flash or scratch - I don't think this is ich.

In the last two months, I have quarrantined this individual twice. I tried two courses of MelaFix + PimaFix on one occasion and two courses of Fungus Clear on the other. Both times, the raised white bumps disappeared after treatment and his coloration improved slightly. However, after a few weeks back in the main tank, his symptoms would reappear. Right now, this serpae has a greyish-white complexion and two raised white bumps. Two other serpaes also have one or two raised bumps. Their eyes also appear very slightly hazy.
The other tank inhabitants are unaffected.

Any ideas what this nagging affliction is?
Should I quarrantine my serpaes yet again, and if so, any suggestions for treatment?

My Q tank is currently occupied with some new purchases, including one snail, but I could move them to the newly set up 7 gal - I have BioSpira to instantly cycle that tank.

 

[Allivymar]

QT em and try a round of broad spectrum antibiotics (maybe Kanacyn?). Even better, if you can get some medicated food, go that route. I suspect some sort of internal bacterial infection that is just not going away as it needs a strong antibiotic which targets the bacteria specifically.

Btw, you should really join me, BrianNY and madasafish at the Greater City Aquarium Society mtgs one of these days at the Queens Botanical Gardens (next mtg is Weds *hint hint*).

 

[QTOFFER]

Thanks, Ally. I'll QT them again *groans*.
I can get my hands on Kanacyn, so I'll try that first. Any idea where I could get medicated food?

And I'll try to make the GCAS meting this week - it's only about 15 minutes from my apartment by bus!!!

 

[Allivymar]

I sure do; this place carried antibiotic flake, anti protozoan flake and anti worm flake: http://www.flguppiesplus.com/_wsn/page3.html . At some point I need to get off my butt and order LOL

 

[QTOFFER]

If I'm going to treat the four serpaes with Kanacyn, I might as well put them into my new, uncycled bowfront (with daily testing and pre-dose water changes, of course).
No sense in needlessly moving the newly purchased fish or mucking up my Q-tank's established biofilter with antibiotics.