It's in the opening credits of True Blood which I have been watching while ill, and I feel now I am up to speed to join in conversations at work about the show I should be able to offer my colleagues a fishkeeper's perspective ... all I know is it is presumably found in a Louisiana bayou and should be some sort of catfish??
I think its a Mudpuppy (Necturus sp.) Its got functional legs and large external gills so it isn't an Amphiuma (Congo Eel) or a Siren.. Axolotls and Tiger Salamanders aren't native to Louisiana, so it probably won't be one of them. I couldn't narrow it down to species however.