Introduction

When Blizzard started revealing details of the expansion, they promised some fresh fish:

"We're still evaluating some ideas for fishing that we're not ready to share yet, but I can tell you that there will definitely be new high-level fish for our anglers to catch in the expansion." - Frank Pearce, Executive Producer, July 2006.
And not much more has been known until now. The information on this page is taken from the beta version of The Burning Crusade. It will probably contain spoilers. Most of this information is first-hand - collect by myself.

Last major update 1 December 2006, based on beta 2.0.0-2.0.3.

Master Fishing

The Burning Crusade raises the maximum possible fishing skill to 375. Master rank is trained using the book "Master Fishing - The Art of Angling". This is sold by Juno Duffrain, who can be found by the Umbrafen Lake in Cenarion Refuge, Zangarmarsh. The same vendor sells both to alliance and horde. The location is relatively easy to reach for someone at level 60 - just head west from the Hellfire Peninsular. The book costs 5 gold and can be resold. The book requires level 45 and fishing skill 275 to read. I assume this means characters not able to use the Dark Portal to visit Outland will still be able to achieve 375 fishing skill.

Each skill increase takes at least 10 catches - the increases are still somewhat random, with a range from 10 to 13. The average number of catches per point of skill gained was:

Skill 300-350: 10.5 catches per skill point.
Skill 350-375: 11.5 catches per skill point.
Increasing skill from 300 to 375 takes just over 800 successful catches. There is no need to fish in Outland - skill can be gained in Azeroth too.

Pools of fish called schools are common in Outland. They behave in the same way as pools in Azeroth - after catching 2-8 fish, each pool disappears. Pools then reappear over time.

Known named fish pools are:

Bluefish School (Icefin Bluefish) - Nagrand.
Highland Mixed School (Furious Crawdad and Golden Darter) - Terokkar Forest (Blackwind Lake, Lake Ere'Noru and Lake Jorune) - see the Catching Furious Crawdad and Mr. Pinchy topic.
Mudfish School (Figluster's Mudfish) - Nagrand.
School of Darter (Golden Darter) - Terokkar Forest.
Sporefish School (Zangarian Sporefish) - Zangarmarsh.
Feltail School (Spotted Feltail) were originally found in Terokkar Forest and Zangarmarsh. Patch 2.4 replaced these with Brackish Mixed School (Spotted Feltail and Golden Darter).

These appear in zones where the named fish can also be caught by open-water fishing, except for Furious Crawdad, which can only be caught from Highland Mixed Schools.

Two further pool types contain other items:

Pure Water (1-2 Mote of Water) - Nagrand - see the Fishing Pure Water topic.
Steam Pump Flotsam (Heavy Supply Crates and Steam Pump Debris) - Zangarmarsh.
Each Heavy Supply Crate contains Elemental Blasting Powder, Fel Iron Ore, Handful of Fel Iron Bolts, or White Smoke Flares.

Pure Water pools look like the Patches of Elemental Water in Azshara. In lower parts of Nagrand, Pure Water pools are mixed with Bluefish and Mudfish Schools. However, the Elemental Plateau (above the Throne of the Elements) in Nagrand contains a separate set of six pool spawning points where only Pure Water pools appear. This area requires a flying mount or (Druid) flying ability to reach. See the Fishing Pure Water topic for more information about fishing these pools.

For a full explanation of how to fish Highland Mixed Schools in Terokkar Forest, including Mr. Pinchy and its Magical Crawdad pet, see the Catching Furious Crawdad and Mr. Pinchy topic.

All pools also sometimes contain the same other (non-fish) items caught from open-water fishing, such as Curious Crate and Goldenscale Vendorfish.