As someone that owns and operates a retail store (not fish related) with 2 locations and knowing a couple local owners here I can tell you a couple things -
1. PROFIT - shipping is a bear, but if you are going to get into fish/coral you'll need a good reliable transhipper. Box costs are around 400 here in western PA but have been creeping into the 600 range.
2. PURE PROFIT - you'll need to be fraggin' to make real money on corals. The overhead alone is daunting but without mother colonies you'll be stuck buying from other vendors for awhile.
3. Fish and coral are extremely delicate in that situation - you need to do something to seperate yourself....like QT your fish prior to purchase. So people could come in, request a fish then you would QT it for them if they wanted.
4. We are entering a "bear market" it's going to be extremely tough to find decent rent and customers for awhile, but you are in a good area. My stores are in the boonies.
5. Establish a business line of credit for the first couple months. It'll cost the loan origination fee but will allow you to siphon money out as needed. Don't expect to be profitable out of the gate.
6. Aquariums suck. The mark up is junk and getting them shipped/arrival in one piece can be tough. Used goods are viable. Do not snub your nose at selling lightly used gear. A good eye for equipment can go along way to help margins.
7. Selling online seems like it's the way of the future (I know, I'm 10 years too late). For maximum returns you may want to invest in this down the road.
8. EMPLOYEES. It's terrible to find them and most of them are "unemployable" in my opinion currently. The American productivity advantage has withered away.
9. Watch how you set it up, you may want to have a corporation, LLC, sole propriety setup...talk to an accountant.
10. FIND OUT WHAT YOUR BOTTOM LINE IS - what do you need to make a month in revenue to be successful? Do a business plan. Find out what other stores are doing. Find store(s) you really like, that are successful, and ask them how they do it and/or copy them. Original ideas don't happen much in retail.
If you have any other questions feel free to PM me. I don't know the ins and outs of running a LFS, but I know quite a bit about running a business successfully.
GOOD LUCK!