Old Ironjaw

Old Ironjaw is an off-hand item. It gives a bonus to stamina.

Source
This items is an extremely rare fish that can be caught within the city limits of Ironforge. The waters in the Forlorn Cavern and the pool in the Mystic Ward have both been cited as sources for obtaining this elusive trophy. The low elevation lava at the Great Forge also used to be a source, but by patch 3.1.3, fishing in this lava began yielding the error message, "There aren't any fish here."

For Alliance, your best chance at getting this fish, while the off-hand stat bonus is still useful, is to train up your fishing skill in Ironforge. Do your initial fishing in a starting zone lake; Ironforge is frustrating when starting. Somewhere around fishing skill level 25 to 50, depending on your tolerance for missed fish, switch to fishing in Ironforge. Use a Shiny Bauble lure at first. Ironforge requires a fishing skill (with a fishing lure) of 75 to have no fish get away. Up to skill 75, each point of skill short is a percent "fish got away".

Horde version
The Horde version of this fish is Old Crafty which can be caught within the city of Orgrimmar. These two fish are the only off-hand trophy fish that give a stat bonus, both give +5 to Stamina.

Achievement
Old Ironjaw (achievement)