Bring a Monstrous Felblood Snapper to Old Man Barlo. You can find him fishing northeast of Shattrath City by Silmyr Lake.
This old man is going hunting soon. I'm gonna take down a mammoth shark off the coast of Azshara.
The thing is, I need a toxin that'll stay on a spear tip while it's underwater. To make that kind of stuff, I need the glands from a poisonous fish: the felblood snapper.
Such a vile fish only thrives in the waters of Hellfire Peninsula and Shadowmoon Valley. Bring me back a whopper and I'll be a happy old man.