Parasite/fungal trouble. PLEASE HELP :(

[rox501]

I have 3 fish with white stuff foring on their bodies, I cant figure out what they are but i know they could not be ich or something of the like> I have a 20 gal hooked up to a fluval 405 with water parameters near perfect; with 7.4 ph, 12.5 ammonia, 0 nitrites, and 0 nitrates. I have 1 gbr, 7 glowlights, 4 skunk cories, 4 tetras of the sailfin variety (cant find name of their species), 6 penguin tetras, and 2 nerite snails. So far the gbr and unkown tetras have the worst of it while one cory has something on its back. im worried out of my mind on what to do plz help. I have pics to help

 

[Mumma.of.two]

I have 3 fish with white stuff foring on their bodies, I cant figure out what they are but i know they could not be ich or something of the like> I have a 20 gal hooked up to a fluval 405 with water parameters near perfect; with 7.4 ph, 12.5 ammonia, 0 nitrites, and 0 nitrates. I have 1 gbr, 7 glowlights, 4 skunk cories, 4 tetras of the sailfin variety (cant find name of their species), 6 penguin tetras, and 2 nerite snails. So far the gbr and unkown tetras have the worst of it while one cory has something on its back. im worried out of my mind on what to do plz help. I have pics to help

Are you sure you mean 12.5 ammonia???? Thats VERY high. You need to do a water change (or more) to bring it down to 0.
Do the fish have a white cottony growth?
How long has the tank been set up?

 

[rox501]

sorry on the typo, i meant to say 1.25 ppm, still doing water change tho

in terms of cotton i guess so but the cory's more worm like, the tank has been thouroly established for a good year, never crashed

 

[Mumma.of.two]

Good idea. 1.25ppm is still high up there in the danger zone.
http://badmanstropicalfish.com/fish_palace/tropicalfish_disease_identification.html#ERM
This will help you ID what's wrong (There are two pages) and we can go from there. Look at columnaris/bacterial infections, fungus, and anchor worms. I'm on my phone and can't see the pictures very well I'm sorry.