Black neon ich

[scotty1301]

I saved 3 Cory's from a 2gallon tank at my lfs but my black neon got ich 20mins later how is this

 

[absolutangel04]

Ich can be present in a fish without being instantly visible. It can live for quite awhile in the gills, and you will not know it is there. It likely came in on the new fish and then transferred to your existing fish.