well for what its worth, this website has 100,000 members. that on an international scale; not claiming this as a factual count of all the reef owners in the whole world. but just saying, 100,000 here, and that surely includes many who dont have a reef at all, just signed up to see what its about. but if you consider this as a rough estimate with offsetting differences for an american count; thats more like .03% rather than 1%. making it 13 people...
ok, with that said i want to be completely clear that I believe the true number to lie somewhere in the middle; but thats a big middle.
other big problem your looking at this as the store being your only expense.
number 1, and its a big one, is your time. I dont know who you are or what you do, but we can assume your time is worth atleast 30,000 a year. so theres expense number 1. and this store will surely require longer hours and weekends that a typical 30k/year job wouldnt.
banking costs, always have the credit card companies good for a nice 2% off the top.
of course cost of goods sold. I have no clue what the typical margin is on fish.
supplies, we all know fish tanks are expensive. lot of salt. electricity, water, filters, ect.
losses, your dealing with live goods. and they are coming to you stressed, and you'll be expected to gaurentee that they then live through the another stressful move. more costs. a stroll through even the nicest fish store and unless they never clean their tank(I doubt it) they must lose a couple dozen fish every day.
now Ive just laid out a bunch of reasons to not do it. IMO you have all the reasons TO do it already. what you need to do is disprove my reasons with reasonably correct budgeted forecasts. maybe go to a neighbooring town or the next closest fish store, and just sit there and see how many people come in each day.
around here there are a few MAJOR stores, petland(most of its business is in mammals and fw, Id be suprised if the SW breaks even) then theres a hard core SW store that seems to do great. but that is serving basicly all of metro atlanta, a few million people.