There are four different water types that a fishing hole can be: foul water, rivers, lakes, and ocean. What type of water a fishing hole is should be pretty obvious based off of context clues, however, sometimes you can be fooled, especially by foul water.

Foul Water
At times, foul water can be pretty obvious to spot, like the urine-colored waters of the Sulfur Pools in Stonefalls.At other times, it can be harder to tell, like this waterfall near the Armature's Upheaval in Stonefalls, which is foul probably because of all the crap coming out of that forge.In foul water, the preferred bait is either crawlers or fish roe, and the fish you can catch here are slaughterfish, trodh and chub.

Rivers
Rivers will be any kind of moving waters, usually starting at a waterfall and ending in either a lake or the ocean. When it gets near a lake or ocean, the water type of the fishing hole can vary. The far side of the river across of Armature's Upheaval is one of the rare river fishing holes in Stonefalls (there's only 2 that I know of and they're both on this side of the river).

In rivers, the preferred bait is either insect parts or shad, and the fish you can catch are salmon, river betty and fish roe (I know roe is an egg rather than a fish, but you still catch it there).

Lakes
Lakes will be any large or small body of water that's not the ocean, like the Steamlake Encampment in southern Stonefalls, that's patrolled by this asshole bull netch.In lakes, the preferred bait is either guts or minnows, and the fish you can catch are spadetail, silverside perch and shad.

Ocean
The ocean is... the ocean. Anywhere you're on the coast, you'll find an ocean fishing hole. Any coastal city usually has docks that are good for fishing, like these docks in Ebonheart.In oceans, the preferred bait is either worms or chub, and the fish you can catch are dhufish, longfin and minnows.So now that you know about the four types of water you can find fishing holes in, let's talk about the 9 types of bait, and where to find them.