Now I'm really worried!

Oh dear,

Following on from the Sad Day thread:

I lost two of my SAE's and two more Neon Tetras suddenly this evening, just
when I thought everything was okay.

I didn't understand why after changing the water two days in a row (100%
changed in two days) and getting my chemistry right and back to stable
levels, why my fish were still passing away.

Some of you may remember I posted a while back about a Serpae Tetra female
that had what appeared to be an eaten away lower jaw due to "fungus"? (read
on because it's a major sign of what I now suspect is happening)

Well all of the Neons that have passed away have had this white-ish band
across their head from gill to gill.

The band appears seemingly over night, then they gasp at the surface, become
disorientated and then die. My SAE's that passed tonight had darker bands
from gill to gill and one of them was being chased literally to death by a
rampant Hockey Stick Tetra who just wouldn't leave it alone.

Considering that several factors have occurred of late in my tank, such as
high temperature (30 C), dirty substrate (only discovered this two days ago
and have vacuumed it clean each day since), low dissolved oxygen (a fairly
rapid raise in hardness and CO2 combined with the high temperature), stress
(trying to catch 5 BATs and disturbing one and all in the process - also
there has been some inter-species, and in-species (being bothered by mates)
spats) and a pretty big fluctuation in water quality, and slight over
feeding it seems, over the last 3 weeks or so;

I have come to the conclusion that what is now really killing my fish of
could very well be *Columnaris flexibacter*.

All the conditions have been there for it to develop and some of the dead
fish have shown mild external symptoms of it (the bands on the heads, the
dissolved lower jaw of the Serpae, and in the case of the bigger of the
SAE's that died - rapid respiration, lethargy and a complete change in
behavior several hours before and leading up to death).

The two Swords that died a few days ago showed no symptoms what-so-ever -
they just died very quickly, and they were both young and visibly very
healthy.

As Columnaris is gram-negative and contagious in warm de-oxygenated water, I
can state that I am *very worried* it's going to wipe the entire fish
population in my tank out.

The treatment I believe, and I need the more experienced people in the
groups to help me out here with this, is to lower the water temperature,
oxygenate, siphon gravel daily (it reportedly can grow on excess food and
waste on the gravel), change water daily and as a final resort dose with
Potassium Permanganate or Sulfur compounds? Does this sound right?

I have to act quickly on this or it's going to wipe the whole tank out, if
it is C.f..

I honestly can't see it being anything other than this because my water and
gravel are right on spec.

I am also guessing this is the price you pay too for not home quarantining
fish before they go into a tank? or are these bacteria always present in the
water column waiting for the right conditions?

If the worst happens and the entire population gets sick and dies, what is
the procedure for the tank itself?

Would you advise breaking the entire tank down, steralising everything
(especially filters and gravel), dosing the plants in Potassium
Permanganate/Bleach/H2O2 or something?

Oh boy, please help if you can - I think I am in big trouble and I'm about
to lose all of my fish

Many thanks in advance,

Oz

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My Aquatic web Blog is at http://members.optusnet.com.au/ivan.smith