Are they outside or indoors?
Either way it looks like overwatering.. They will bounce back though, I see it alot here in WA with my plants once they are outside during early spring when the rains around more than the sunshine.. Since your in OR I can imagine you might have the same problems.
Leaves start to turn that color when they don't recieve enough sunlight and recieve too much rain outdoors. They go back to emerald green once the sun starts to hang around longer..
If they are indoors cut back watering alot and spray with epsom salts (at night so it doesn't burn your plants)
This is just me but it is not any sort of fungus.
Good luck
Brandon