I hate to say it, but petsmart is going to be your best bet near here. I was told of a "mom and pop" in Warner Robins, but when I got there it turned out they only had a 20 gallon tank with some random guppies.
Definitely, there is Athens Aquarium Supply, I think thats the name. Its off of Broad Street behind Checkers on Old Epps Bridge Road. There are a lot of chain pet stores in the area like Petland and such in the area, But its a toss up if they have anything of quality.
When I lived in Athens, if I didn't find what I was looking for in there, the store show tank made it worthwhile.
You can go to Noah's Ark off Hartley Bridge Road, next to Kroger. They carry basic plants, but I never had a problem with them ordering special for me. On rarer items it may take a week or two, but they've helped me with my saltwater tank and freshwater tank.
Noah's Ark is ok. They don't have a ton of stuff but they will order things for you and they were the only place (back in the day) where i could find java moss and water lettuce for sale
every once in awhile they'll have some neat little hard to find fish that you won't have seen before
Other than them there is a little mom and pop place that basically only has puffers and cichlids. its in Bonaire, i think, next to a liquor store. i was in there once and it was ok. No plants that i saw though
there's a 3rd place called Macon Pets or something similar with a pretty decent selection but everything was too much and i didn't see any plants there either