What is going on?!

[jerbear]

I do not understand why my mollies are dying, I know I meantioned it before but I am now down to 2 black mollies out of the 6 I had. My guppies and noens are all well and thriving........I just dont get it. I read on a site about "molly disease" does anyone know about it? The sites I have read are very vague and one even said to add 1/4 tank of seawater to treat it. I also read there is a product called "molly shimmy treatment" but cant find it anywhere. There is no visable signs of illness except "shimmies" for a few days then dies. Any thoughts?
tank=20 gal 4 guppies 2 mollies 3 noen tetras
ammonia=0 nitrate=10 nitrite=0 hardness=75
alkalinity=120 ph=7.2

 

[OrionGirl]

You'll need to pick between hard and soft water fish. The harder water that the mollies prefer will not be appropriate for the soft water neons. You can try getting mollies from a breeder that uses softer water, but IME, mollies just never do well in low TDS water.

Not all fish are a good mix, even if they get along.