You probably know all about the --they're fairly common in the rivers of Terokkar Forest and a delicacy for priests. But here's one you haven't heard of: the blackfin darter.
The fish is notoriously crafty and difficult to catch. You have to pull your line at the last possible second, because they nibble at the bait before they take it.
Drop your line in the rivers of Terokkar and bring me a black darter. Avoid the lakes, as the blackfin only thrive in moving water.
How's the fishing today, <lad/lass>?
Well look at that... you caught a big one! This old man is eating in style tonight.
The quest instructions do not mean to wait until the fishing channel bar is almost depleted. To successfully complete the quest, you must pull in your line about a second or two after your lure has bobbed: in other words, fish as you normally would, and you will eventually catch it.