I only ever look for one thing in on line fish. I look for fish that are hard to find locally. If a remote vendor has what I want and I cannot get it locally, I will buy on line. If I can get something either place, my LFS gets the business almost every time. Shipping costs so much that the small cost savings on each fish is way offset by the shipping charges. Try an example, a real one that I did. I bought some Corydoras hastatus for a mere $1.50 each, which sounds very cheap when most cories cost about $4 each and the hastatus were not even available locally. End result, the cories cost $1.50 each so that is $18 for a dozen fish, another $30 for express shipping so that the fish would arrive in good shape. Total for 12 fish was $48 for 12 fish or about $4 each. If I had not wanted that many fish, each one would have cost me more than buying locally. Now I had placed myself in the hands of someone that I did not know and had bought a dozen fish based on textbook descriptions and internet pictures of the fish he had in stock a month ago, not the ones I was buying. Why would I do that if I could go down the street, inspect the fish and buy as many or as few as I wanted for the same price per fish?
I find internet sellers are generally good business people and try hard to give good service and value to the customer but my trust is hard to gain and very easy to lose when you are just a name on the internet. A hard to find fish, not a bread and butter fish, is the only thing that would get me buying on line under normal circumstances. I do make an exception for a club like ALA doing a fund raiser by selling on line. I know the organization and I really want to support them. In their case I make the exception, and am even willing to pay a bit of a premium for their fish, but I lost that auction bid.
Also have a variety of pictures! So we know what where buying 
you just learn for mthe mistake dont buy them from that seller..
