I would ask for a manager then hand him a resume with a filled out application. You will get a very good rep if you start early. In your resume I would talk about what animals you have cared for and how long. Tell him that you are on this site always reading about SW and FW fish. That way he knows that you know somethuing regarding any fish questions that customers may have. If he asks you a question don't sit and think you should try to know it right away and don't interupt him while he is asking. Now you can extend the truth when talking about your research BUT becarefull cause it may come back and bite you on the butt.
But I would do the resume just to show that you have some class and is willing to take this job seriously. Try to get his/her business card and right after you meet with him then I would get orwrite a thank you card, saying something like "Thank you for takeing the time to meet with me on ________, and I'm looking forward to be doing business with you in the future. Something like that. I did some hireing at one of my old jobs and those kind of people had a better shot then others. Your age might be hard BUT if you visit with him on a regular basis or VOLUNTEER you will be more likely to get it when you are old enough. Hope this helps.... Rick