Yes, I can't say for sure that it is ich, but a tang in a small tank rings alarm bells. What happened to the 180g upgrade you were planning? Do you have a QT? There are plenty of threads on here about ich. Only 2 cures I am afraid and both are recommended in a QT while your display remains fallow ( empty ) for at least 6 weeks. Only a fish free tank will allow the ich to die and don't be fooled if visible symptoms go away, it is still there and can come back at a later stage, often worse. Have a good read up on it and good luck, I hear its a tough battle...