What could this be?

[It's Me]

OK so I have decimated my fish population over time. I think the problem came in with one of my guppy's she died a few days after she was put in the tank and now my other fish seem to be dying off one at a time. It starts with what I thought to be a fungus. White cotton looking spots about 1mm in size usually on the fins. this eventually eats through the fins and will leave holes. Then the fish will get these spots on its upper body. These will go from white to what look like flesh wounds. I am not experienced at all so I don't know what this might be. I thought the spots were to big to be ich, but I don't know. please any help would be appreciated. Here are some pictures of the latest victim, my Gourami. I now have a quarantine tank/hospital tank that he is currently in.

20g tank
PH-7.2
kh-80
GH-75
no2-0
no3-10

Temp-78

 

[guppy]

This seems to be saprogenia fungus and should respond to a malachite green/formalin based med, or to nitrofuracin green. You should also check your water parameters for fluctuations, especially pH levels as this disease is usually brought on by the fish being in an unhealthy or stressed condition and rapid changes of pH will stress the fish.. The gourami looks malnourished.