datetime to_s(:option) not working

I added a migration to add a datetime object column to my database. It
all works great, and I can edit it and everything using the
select_date helper for forms.

BUT when I try to format the date using gallery.gallery_date.to_s
(:short) I get an error:

"wrong number of arguments (1 for 0)"

How do I do this?

Shouldn't it be