Fishing pools, or Schools of Fish, are location objects found in different bodies of water in WoW that have a significance to the fishingprofession. Typically, a higher portion of more desirable items can be fished within a fishing pool. Fishing pool is a more general term; School of Fish is a fishing pool that contains (primarily) fish. School of Fish can also mean a kind of critter object in WoW that is not directly fishable (but appears only in fishable waters), and so fishing pool is more specific as regards the fishing profession; School of Fish critter objects are not fishing pools.
Fishing pools are shallow cylindrical regions within fishable water. They designate small regions within fishable water that give better kinds of catches than the surrounding water. Some fish can only be obtained from Fishing pools.
In order to fish a Fishing pool, your bobber must be within the circular area on the surface of the water that defines the boundaries of the fishing pool. Only the top surface has significance for fishing.
To do this, face the pool, pole in hand. Cast, then if you want to only fish the pool, recast each time you miss. An AddOn such as Fishing Buddy can make this easier to do.
If your bobber lands close to the boundary of the pool, it may be unclear if it is within the pool or not. You can often tell from what you catch, but if you are in a hurry you may not want to wait.
Some of the uncertainty is from the 3-D nature of the pool. Depending on the type of pool, it may be partly outlined by fish critters swimming within the pool boundaries. These will be under the surface of the pool and from your point of view will appear to be offset toward you on the surface. Also, some of the defining graphics fade in and out, simulating the effects of light on water.
Another visual challenge is that the barrels and crates in a Floating Wreckage pool can somewhat obscure your bobber. Also they are slightly bobbing, and can make your bobber seem to be bobbing prematurely relative to themselves.
The fishing skill level required to fish a fishing pool is the same as the surrounding water. If the pool spawns on a boundary between fishing zones (there are some that do), the skill level required may be different within the fishing pool depending on where your bobber lands.
Fishing pools are not permanent, but appear and remain until fished out (like mineral nodes are mined out) then respawn at a different location. The respawn rules vary, some types have a delay, some do not.
Schools are important objects for selective farming of Alchemy or Cooking ingredients.
There are some pools that, while visible at the water surface, are not used as a fishing resource. These may be used as quest objectives or to summon a boss. These have a slightly different appearance than normal fishing schools. A normal Fishing school will look like a circular outlined darker patch of water. A quest objective pool will look like a speckled surface area.
'School of Fish' which is a pool of Peacebloom exists in the game in a lake in the mountains north of the Human starting area Northshire Valley. You can see it as you fly over it on the flight between Stormwind and Ironforge. You cannot reach it by normal means, but it has been fished. It is probably a code test area or a bug, and fishing it might be considered to be an exploit, although the peacebloom is not of noteworthy value.
Achievements
The Following Achievements Require Fishing from Pools: