Greetings. There are some reef / fish stores near Santa Rosa. In order of proximity to Santa Rosa, there's Caesars in Santa Rosa, North Bay Aquatics in Cotati and Jofish in Petaluma. There's also Coral Reef Eco Systems out towards Guerneville which is run by the proprietor out of his house.
And if you can get down to San Francisco and / or San Jose, there are more reef stores down that way too.
Enjoy your stay in the bay area.