There is a huge difference between fishBUYERS and fishKEEPERS, you cannot buy every new "fad" fish and sell it when it is no longer cool on the boards. Those folks burn out, they do not love the fish, they love the attention they receive.
I started a thread to discuss the difference it was closed, I never heard why, I asked one on the mods/admins and never got a response.
Think about it like dogs, if you bought every new dog out there eventually you would be soon overun and the dogs would suffer, that is what happens with lost of fish, it just never makes the news like dog abuse does.