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The Fishing Pond is the easiest and most fun source of life and mana recovery items. These fish can be used at any time outside of combat and performing a skill. If you are fortunate enough to find a fishing pole, you may equip it at the first fishing screen. Free loaner rods are provided for you regardless if you choose to use your own rod. Be careful though, as if the fish wins the struggle to be captured, your rod may break!
To reel in a fish, click the Life Bar with the ? ? ? as the label. When the word "Snag!" appears, the fish has twisted your line and you need to counter this by hitting the Snag Counter button below its life bar. If not, the fish will put extra tension on your rod and you risk losing your prize, and possibly your rod.
When the fish's Life Bar is empty, the fish will appear as an item below the life bar.
One should note, fish aren't the only surprise you can find in the Pond.
this one might help you as well, it was released soon after the fishing update to help people catch the fish
http://forums.d2jsp.org/index.php?showtopic=23940639&f=272