Yes, you can eat them. AFAIK they generally get into ecosystems as discarded pets and are generally illegal to keep in the US.
My ex and I had one a looooong time ago, from a fish store that had a variety of fish (and croc) they should not have had as they were illegal. The fish really was such an awesome keep though, super personable and interesting to interact with (we also kept south american Cichlids). It is a shame they are so terribly invasive and adaptable.
Hopefully GA can get them out of their environment!