Fishy letters are those letters that are used for dumb people's captions
These are fishy letters:
Lisa: how was your day?
Dumb person: o0hH iT w@s aMazIng, i At3 f1sH!!!
What someone says about their optometrist when he is being a butt (mean, stupid, or smelly) or not being an optimistic person
My optometrist is mean... He is a butty optometrist.