Agreed. Be a professional with your complaints and you'll be more likely to get a positive response.
Hmmmm....I think professionalism didn't even have a chance here. Maybe you missed this part:
He told me I was crazy
Or this:
He retorted with a "what do you know?!" under his breath and I heard him
If I were in this situation, I would have immediately asked to speak with a manager. I probably would have done so, anyway, regarding the lack of knowlege of how to handle fish, since it was obvious this guy wasn't going to listen to a customer. I probably would have had a very loud conversation about the improper treatment of customers and fish...just loud enough for surrounding customers to hear. That way, I could have either, A) gotten a free fish to shut me up or, B) gotten thrown out.....which wouldn't have mattered to me anyway since I probably wouldn't have spent money there after that.
I agree that you (twig) probably should have taken your business elsewhere. Like I said, hit 'em in the cash register.