Sick tetra

[darbyy7]

I have three von Rio tetras in my tank. Recently one became very big and round. I thought it was pregnant but now I noticed that it is losing its stripes and red color. It's mouth is also a little rotted.
I've had mouth rots before on bloodfin tetras from high nitrates and nitrites and treated with a stress zyme which fixed it.
It's the first time I used a test kit (I've always taken water to a pet store test) but my results are
Nitrate 20
Nitrite .5
Hardness 300
Alkalinity 0
pH 6.8
What is the problem with my fish?

 

[hollywood11892]

bump i would like to know as well

 

[darbyy7]

Well I had to flush my fish =[ the scales started to pop out and mouth rot started. How do I help my water???

 

[jrw1660]

The fish becoming bloated and the scales popping out or "pine coning" may be dropsy. I lost a Tiger Barb to it. My water was fine, but he wasn't passing fluid properly. I added some extra aquarium salt to help the other fish and fed them Meto+ for about 4 days mixed in with frozen blood worms. No other fish developed any symptoms of dropsy. From what I understand if the fish is to the point of being swollen and the scales poking out, there's not much you can do to help it.