fishingFollow

In old world, Stonescale Eels and Deviate Fish are good money makers too, in Outland there's plenty to fish and lots of cookable ones, don't think I've found any alchemy fish yet though. And then there's Vendorfish, that sell for like 6g.

If your fishing skill is high enough, about 200-250, you can fish in Tanaris and Feralas and catch stonescale eels that still sell fairly well on some servers. During the wintertime, I find that winter squid sell fairly well, too. Deviate fish are found in The Barrens in the stagnant oasis and your fishing level doesn't have to be very high there, probably the same as fishing in Westfall. In order to catch fish in the Outlands, your skill should be at least 300, not to mention that your character has to be level 58 to go through the dark portal and you must have the expansion installed.

A stack of blackmouths go for about 1g on my server whereas I can get 8g or 9g for a stack of stonescale eel.

Check your AH for pricing on your server.