Dieing fish please help

[Anaxis]

I got home today and found that my wife had to give my red turquoise discus a proper burial, there is another that seems sick as well as my black ghost knife. There are in a 60 gallon along with mollies, plates, guppies, and some nw cichlids. All the others seem fine aside from the discus and the bgk. The water is a greenish cloudy color. It has no ammonia, nitrates, or nitrites. The tank is dual filtered with a fluval 305 and a aquaclear 110/60.
Now to the description of the sick discus:
Whitish coat along the top and bottom of the body where the fins start, about where the lateral lines are. No spots just a film.
The bgk looks normal but I found him in the bottom of the tank on his side gasping.
I immediately placed both of them in a hospital tank, treated it with kordon ich rid+, Maracyn, and aquarium salt.
The bgk is now moving around in the tank and becoming active again, seems to have snapped out of it for the time being.
Any suggestions as to what might have caused this and is treating for ich and parasites more appropriate than treating for fungus?

 

[HUKIT]

Your stock list and fish choices need to be addressed in the future, but for starters please provide water results since it's impossible to have zero nitrates unless your heavily planted. How long has the tank been running? Are there any new addition of fish within the last 30 days that were not quarantined?

Stress also plays a vital role in fishkeeping, so overcrowding certain species will be effected more than others. Just like people the effects of stress are harmful and fatal in some cases. Short-term stress will cause an increase in heart rate, blood pressure, and respiration. The fish is reacting much as we do with the fight or flight mode. The fish can only maintain these altered states for a short period of time and then they will adapt or the stress will become chronic. Stress is accompanied by the release of the hormone cortisol, which is responsible for many of the negative health effects associated with stress. In addition to having a negative effect on growth, reproduction, and digestion, chronic stress will also lower the ability of the immune system to respond effectively and fully. This lowered immune response is what allows parasites, bacteria, and fungi to infect a stressed fish and cause disease and death.

 

[Anaxis]

Yes the aquarium has a lot of plants. It's been established for about half a year already. I know that I'm not really supposed to have certain species with others but they actually get along fine, no territory issues or nipping. All seemed well. I was doing my PWC once a week @ 25%, and replacing filter media in stages.

 

[Anaxis]

Chilodonella is what I have. I lost both discus, my black ghost, a glass cat, 3 neon tetras, and a guppy, all within 24 hours. Apparently the onset is sudden and without notice.
The water quality is good, 6.8 ph, nitrates are less than 10 ppm, 78 F.
The only thing that has been introduced to the tank in the 2 weeks prior is the changing of carbon on one of the filters, and also hikari frozen bllodworms, spirulina shrimp, and daphnia.
I'm treating with maracide.
All the other fish seem to be perking up at this point since I started the treatment.