I like it when I can feel free to ask about the quality and health of the animal, and get an honest response. Honesty is one of the most important things, I think. I'm not going to trust some sketchy guy who seems like he would have no problem sending home a little girl with two goldfish and a one gallon bowl.
For some reason it makes me feel better to hear "Yeah, Yellow Tangs are great, I have one myself - you might want to try some Nori, mine just loves it" than "Um.. your total is thirty bucks". I feel better about purchasing from a person or a store that has knowledgable employees with experience, and has a passion for the hobby, rather than just treating the animals like dry goods.
I *LOVE* it when they have one or more display tanks set up, showing how impressive the hobby is when you aquascape and put time and planning into this, rather than just dumping some fish in some water and wandering off. It gives me some ideas for my own tank, and it shows me that they aren't complete morons.
I don't like it when they assume from the get go that you don't know anything because you haven't shopped there before. I don't like to be looked down on with *that look* and have them say something like "You know.. these don't stay the same size". While it's important to know the adult size, and the requirements for the fish, it can be done without the attitude.
Fish snobbery really gets to me. "Saltwater is better than freshwater", "Freshwater is better than saltwater" and the general sneer I seem to get when I buy feeder goldfish.. and respond to the question "What are you feeding them to?" with "Nothing, I like goldfish".
One thing I will suggest is that you make some sort of guarantee. I can't tell how annoying it is to buy a fish or invert which looks perfectly fine, get him home, find a problem in a day or two, come back, discover that THEIR fish or invert has the same problem, but worse, and discover that they don't guarantee SW
fish at all - ever.
Guaranteeing your fish builds confidence in your customers, and is a gentle reminder to keep the highest standards for your store and livestock.
Even online fish stores give up to ten day guarantees for their animals. If they can do it, you can do it.
Good relations with customers are also important. I had purchased some macro algae online, and it hadn't shown up. I emailed them. It was a problem beyond their control, but they still apologized, and sent me a double order free of charge. They can rest assured that they're getting lots of my business in the future, and get free advertisment via word of mouth.
is an expensive hobby, and if you build good relations with your customers, it *will* pay off. Fishkeepers will drive for several hours at times, just to get livestock from a good store. If they buy livestock there, there's a good chance they'll also buy dry goods from you.