Very preliminary, but I discovered today that you can fish in the sewers in Dalaran, first place I've seen in there that didn't tell me there were no fish there.
I've seen 3 fish so far (pygmy suckerfish, glassfin minnow, and bonescale snapper). They're all white text, so you can't eat these for health or anything, but they're probably cookable at some point.
Looks like my leveling is on hold, I'm off to find more!
(got quite a few 'fish got away' wearing just my arc pole and the hat/boots, but with the hat lure applied, I was getting pretty much 0 misses, and the fish were coming up 2 at a time).