fish specific sickness

[BK]

Is there any sickness or disease that would cause only my gold danios
and harlequin rasboras to die?

I have a 125 freshwater with rosy barbs, neons, danios, guramis and
tetras. Most of my fish live 3-5 years. For the past 3-4 days I have
been losing these two specific breeds at a rate of about 2 -3 fish per
day. No physical signs of disease or sickness. One day fine next dead
and only these two breeds. All other fish are fine.

My parameters are 0 ammonia, 7.5 ph, 0 nitrites and 25 nitrates and
water is crystal clear.

Thanks

Brian

[Geezer From The Freezer]

no clue, I'd start with doing some water changes!

[NetMax]

"BK" > wrote in message
...
> Is there any sickness or disease that would cause only my gold danios
> and harlequin rasboras to die?
>
> I have a 125 freshwater with rosy barbs, neons, danios, guramis and
> tetras. Most of my fish live 3-5 years. For the past 3-4 days I have
> been losing these two specific breeds at a rate of about 2 -3 fish per
> day. No physical signs of disease or sickness. One day fine next dead
> and only these two breeds. All other fish are fine.
>
> My parameters are 0 ammonia, 7.5 ph, 0 nitrites and 25 nitrates and
> water is crystal clear.
>
> Thanks
>
> Brian

It's not at all unusual to have a disease wipe out a specific breed of
fishes. It's less obvious in home aquariums because the conditions which
stress the fish are usually severe enough that the disease gets a hold of
everyone, just in a sequence, with a few less-susceptible survivors.
Anywhere there is high traffic, with fish going in & out, the fish's
auto-immune system is under a constant barrage, and healthy fish will
show no symptoms. Then a specific breed will become sick while the other
fish remain unaffected. I've seen this happen in mixed tanks on loaches,
SAEs, livebearers, Harlequins, Zebra danios, Neons, Tiger barbs,
Angelfish, Discus, Bala sharks, Plecos etc etc. It's more obvious in
larger tanks with more varied mixtures of fish.

One danger is that while the diseased fish are in the tank, the pathogen
uses the hosts to increase their numbers and/or their effectiveness on
the less-immune fishes. Then you will see the disease jump over to
another species. Another danger is that the disease might be given an
advantage if ingested (healthy fish eating dead fish). Quite often, the
disease dies with the last member of the susceptible species, and without
a host, the aquarium becomes safe for that fish species again after a
period of time, with no human intervention. Other times, it becomes a
death trap, whenever that fish species is re-introduced.

On the up-side, you are running a fairly stable healthy tank. There is a
killer disease circulating which most of your fish are resisting. In the
alt.aquaria NG, Frank often gives out disease treatment advice (I
cross-posted you there). I have no qualifications to give vet advice.

FWIW, I've found that gravel vacuuming has sometimes helped, as many
parasites have a lifecycle in the gravel, and whether they feed off of
the detritus or just have a reproduction stage there, vacuuming reduces
their numbers, or suitability of conditions. After that, I start
treatment for parasites, then bacteria, protozoans and fungus. That's
just what has worked miserably for me, so I'm still learning.

NetMax

[BK]

I do 30+% every week?

Geezer From The Freezer > wrote:

>no clue, I'd start with doing some water changes!