I've been thinking about the same thing. The best way I can think of to start a club is to first make it an online registry-type thing. Make a club email and blog and have people send in their info to join. If enough members join, you can have monthly meetings in real life to get to know each other and swap supplies/fish. If you only get a few members or they don't want to meet in real life, you can just post articles, ads, and news on the club blog. Here's what I thought the registration form might look like:
Age (Members under 16 will probably need someone to drive them to real life meetings):
City of Current Residence:
Do you breed fish? Yes No
If yes, what species?
Do you culture your own live foods? Yes No
If yes, what kind?
Do you have other aquatic organisms of interest (besides fish)? Yes No
If yes, what are they?
Do you have aquatic plants? Yes No
Do you have saltwater invertebrates? Yes No
Circle any areas in which you have experience: Freshwater aquariums and fish, saltwater aquariums and fish, brackish aquariums and fish, planted aquariums, DIY (stands, aquariums, filter systems, other: _____), pet store aquariums, public aquariums, breeding fish casually, breeding fish for profit, aquarium-related chemistry and science, other: ______________
Circle any areas about which you would like to learn more: Freshwater aquariums and fish, saltwater aquariums and fish, brackish aquariums and fish, planted aquariums, DIY (stands, aquariums, filter systems, other: _____), breeding fish casually, breeding fish for profit, aquarium-related chemistry and science, other: ______________
You can ask if the local pet stores will hand these out for you or just hand out the address of your club blog/email. You can also advertise the address of the club blog/email in your local newspaper. Try to post something new on the blog at least once a week. At the end of each post, you can put a link to the registration form so people happening by will know how to sign up.
For monthly meetings, you can meet up at a local pet store, restaurant, park, or even at someone's house. I don't know what you would do once you got there, but you want it to be a positive experience and focused mainly on aquariums.
That's about all I can think of.