FishNoob wrote:
In article ,
says...

Is it mostly your mollies getting sick? Your water may be too soft for
them. Mollies seem to like either hard or slightly salty water. Plants
will tolerate 1 tsp/5 gallons of salt (0.02%) and sometimes even that
much helps mollies stay well.


The mollies are where we notice the ich and the fungus, since most of
them are black, but there are also danios and neon tetras in the
tank, and I assume they are also affected - and not easily treated
with salt. Yes, the water is soft; I wonder if that's part of the
problem. What could I do about that?

If you don't see spots on the danios and tetras, don't assume they're
affected. Many fish become immune to ich after they've been exposed to
it once. Mollies in soft water are particularly susceptible to
parasites like ich and velvet and don't seem to develop immunity as easily.

Putting the mollies in salted quarantine serves another purpose. If
your other fish are immune, any parasites in the main tank will die off
in a couple of weeks while the mollies are out of the tank. You could
add a formalin remedy to the main tank if you're concerned but I think
you'll only stress the fish.

As I said above, I think a bit of aquarium salt will help your mollies
stay well. Some people also copper as a preventative, but you can't
keep snails or shrimp very easily. "Shimmy blocks" contain gypsum to
harden the water and copper. IIRC, Molly Bright is also a copper
preparation with a bit of salt. Be careful with the copper - it's hard
on tetras and more toxic in water with low kH.

I wish I had soft water - I've got good molly water here but my favorite
dwarf cichlids and cardinals hate it. You might consider platies if you
want more livebearers. They are more tolerant of soft water than mollies.

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