It can be if you dont do anything for your mollie but you'll be able to get the stuff tommarow without losing a fish. Ich can kill a fish if it is not treated.
What temp is your tank set at? Do you have any aquarium salt? The best thing is to raise temp up to at least 84 degrees and add aquarium salt - 1 tbsp per 5 gallons.
Do a search on Ich...there are lots of threads talking about treatment.
Mollies can be very prone to getting Ich.
Good Luck!!
If all you have is mollies, they should be fine. Do a water change then add the salt. While you are treating you should continue water changes, but remember to replace the salt that was taken out.
I wouldn't add any other fish to the tank until the Ich has gone away.
