Always best to disclose.
And why did you pay it off. You should have contested it. Check what the charge says - is it the same as shop lifting? Is it classified as a crime?
Is there a report? If yes, get the report, read what is in it. Have your version ready - i.e. admission of guilt which you already have by paying the fine.. but what you will say to the visa officer/immigration officer only IF questioned about - there could be a story .. you didn't know where the ticket counter was and you were looking for one.. or you forgot.. etc. that you know best.