Here's a list I compiled of items I've received from opening these fish so far..

Felweed, nightmare vine, netherbloom, adamantite ore, khorium ore, stranglekelp, seaweed, darkclaw lobster, eternium ore, ancient lichen and a dawnstone.

Mind you that this was tallied after using about 2 dozen 10 minute lures, and the rate of catching these fish seems rather low (about 1 in 20-40). The dawnstone I got was caught within the first 24 hours after QD first opened up, and was probably removed from the drop table during one of the many shutdowns that followed, as I've NEVER seen another blue gem or anything of that quality inside one of these fish. Basically, unless you have a lot of free time on your hands, it's not worth bothering. I personally won't be fishing these anymore now that I'm under the assumption that Blizzard removed any potential high quality drops from the loot table. You're free to add to this list, even encouraged if you happen to find something I haven't.