HELP! corys may have ich!

[Deaths Sting]

i bought some new corydoras sterbai the other day and it seems they have developed ich! or some type of fungus that resembles ich..

Symptoms being shown:

-lack of appetite
-small white clusters
-deterioration of the tail

tank stats:
15 gallon planted

Filtration: AC 20, air stone

Stock: 10 cardinal tetra (no signs of ich) - i have had them for about 2-3 months now

1 adult corydoras sterbai (no signs of ich) - i have had it for about 2-3

5 Juvenile corydoras sterbai (2 showing signs of ich.. one of them is on its ''last leg'')

Parameters
Ammonia: 0
Nitrite: 0
Nitrate: 0
KH: 0
GH 75ppm
PH:6

Photo of the sterbai that's on its ''last leg''

 

[Deaths Sting]

that cory just died..

 

[haynchinook334]

bump temp to 86 degrees....add salt.