That's good spending money for a kid living with their parents, but for an adult paying bills (even for a fish set up), that's not much. I used to earn anywhere from 6 to 12 grand with sideline fish projects, and that helped a lot. But selling fish online never made me more than 600 a year, with our short season. I could make 1500 a year selling in local clubs, which bought me some fish. We are going to pay for our anti-social ways in letting club culture die.
To clear 600 a year, I bred a lot of species. Most packages sent were for about $30, with another 40 to 50 spent on shipping.