Spoiler warning: if you don’t want to know the disgusting but highly interesting things you’ll coax out of the Dalaran sewer system, just keep scrollin’.

You’ll find an array of new fish and pools in Wrath, but for my money the two great joys are fishing in the Dalaran sewers and the Dalaran wishing fountain. The fountain is actually the more interesting of the two for a reason we’ll cover in a bit, but you’ll also need the sewers if you’re interested in a new noncombat pet and the Accomplished Angler achievement (the one rewarding the “Salty” title, which I’m sure no one in the game ever intends to abuse).

I have a confession to make; I love fishing. Most people seem to hate it, and it’s certainly not one of the more popular professions to level, but I could pass a perfectly entertaining afternoon ingame doing nothing more than chatting on vent and emptying pools of delicious and lucrative fish. Blizzard made a lot of effort towards improving the fishing experience in Burning Crusade, and tons of people wound up leveling it for a shot at Mr. Pinchy, the Find Fish skill, or the high-end raiding food buffs like Spicy Crawdad and Blackened Sporefish.

Fishing is not yet entirely implemented as of Beta Build 8788, so the levels of fishing required for each zone may not be entirely accurate. The required skills:380 to 475; the possible zones are the Borean Tundra, the Dragonblight, the Grizzly Hills and the Howling Fjord. 
Fishing (Grand Master)£º Higher skill increases your chance of fishing successfully in higher level areas, coming from Trainer.
The required skills: 405 to 500; the possible zones are the Crystalsong Forest and the Dalaran. 
The required skills: 430 to 525; the possible zone is the Sholazar Basin. 
480 575 The Frozen Sea. 
The Frozen Sea is the deep water off the coast of Northrend. It is not technically its own zone, but it does have special higher fishing requirements, unlike most of the deep waters of old-world Azeroth.
New Fish Types and its Locations:
A variety of new fish are being introduced in the expansion. Fishing is not yet entirely implemented as of Beta Build 8788, so the locations of these fish may not be entirely accurate.
Barrelhead Goby: From the inland waters of Sholazar Basin.
Bonescale Snapper: From the inland waters of Borean Tundra, Crystalsong Forest, Dalaran, Dragonblight, Grizzly Hills, and Howling Fjord.
Borean Man O’ War: From the coastal waters of Borean Tundra, Dragonblight, Grizzly Hills, and Howling Fjord.
Moonglow Cuttlefish: From the open waters of The Frozen Sea.
Musselback Sculpin: From the coastal waters of Borean Tundra and Dragonblight.
Nettlefish: From the inland waters of Sholazar Basin. (Also from Nettlefish Schools.)
Pygmy Suckerfish: From the inland waters of every Northrend zone. Looted along with other fish types in a single catch.
Rockfin Grouper: From the coastal waters of Borean Tundra, Dragonblight, Grizzly Hills, Howling Fjord, and The Frozen Sea.

Deep Sea Monsterbelly: From the open waters of The Frozen Sea.
Dragonfin Angelfish: From the inland waters of Borean Tundra and Dragonblight.
Fangtooth Herring: From the inland waters of Grizzly Hills and Howling Fjord.
Glacial Salmon: From the inland waters of Grizzly Hills and Howling Fjord.
Glassfin Minnow: From the inland waters of Crystalsong Forest and Dalaran.
Imperial Manta Ray: From the coastal waters of Borean Tundra, Dragonblight, Grizzly Hills, and Howling Fjord.