On Sun, 29 May 2005 12:23:31 +0100, "Gill Passman"
gillspamattaylorpassmanspam.co.uk wrote:

Hi All,
This is really a continuation from the Sick Mollie in my son's tank and
subsequent loss of two Mollies last weekend. I did my normal check this
morning and now one of the Rosy Barbs is on her way out. Checked the water
pH 8 (normal for our tanks), 0 Ammonia and Nitrites and Nitrates are at 5.

No new fish added for months. Tank has been running since last August.

Tank is around 15UK galls. Current occupants are 1 mollie and 4 Rosy Barbs
(around 10 inches of fish maximum). Plenty of plants. Water changes are
weekly 20-30%. We've had very few problems with this tank until now.

I just can't figure out what is going on here or what to do next. If the
remaining Rosy Barbs would be OK with Gouramis I suppose I could move them
and then strip down the tank - this is the only thing I can think of for
now. But I hesitate because I don't want to risk infecting any of the other
fish in the other tanks.

Does anyone have any clues as to what might be happening or what I can do
next to keep the remaining fish?

Thanks
Gill


If I try to rule out causes of death based on your info and the info
you've given to others: It doesn't appear to be a common parasite like
Ich, or velvet because you see these on the fish. Internal parasites,
worms or flagellates or whatever will usually show symptoms of the
fish getting thinner, wasting away, the feces might be weird, white
and stringy or no feces at all from the fish. So I rule out all of
these.

I rule out poisoning be it from ammonia or nitrate or metals or
something weird gotten into the tank because the fish should show
signs of poisoning: breathing faster, panting at the surface or at the
bottom of the tank.

So what's left? I think your pH is a bit high, but if others want to
say that it's fine for these fish I'll take their word for it. I don't
pay much attention to pH anymore because where I live it's 7.0 out of
the tap.

If it's bacterial in nature as Elaine suggests, the way it works, as I
understand it, is more or less like this. These bacteria which can
cause illness, Aeromonas or Mycobacterium or whatever their names are,
will always be present in your tank just like the bacteria you want in
the tank, the species which break down the ammonia and nitrites. These
evil bacteria will grow in numbers if the tank is generally not clean
enough. Keep these numbers down by vacuuming gravel and changing water
more frequently and diluting out the little buggers. The gravel in
this tank is vacuumed all the way to the bottom glass of the tank? I
ask because I think these bacteria live and multiply down there where
there is less oxygen in the water surrounding the gravel.

If this is a bacteria problem, I don't think these fish in the tank
will infect fish in other tanks. The bacteria in question are already
in the other tanks in certain numbers anyway. I think what I would do
is move all the fish in with the gouramis, and tear down this tank
completely and start it over. If you decide to do this, after you
remove fish and plants pour in some chlorine bleach and stir up the
gravel and wash it out the following day. Everything will be
killed/disinfected by the bleach.

-Derek