I am trying to get a job at an exotic pet store with reptiles and fish. They say that they need people who know about reptiles and saltwater fish. I know plenty about reptile care, feeding, handling, etc. but I am not a saltwater fish expert. I know about pH level, but what would be some good fish information to impress the owner with. Good, impressive reptile info is also appreciated. (I put this question in fish because I need to know the fish info most of all!) Thanks!

PS: It is a single store, not a chain.