Well i know this is the "Elite-Exploits" section but i didnt want it to get overcrowded that fast on my realm so im posting it in here, if it bothers anyone feel free to report this thread so it can get moved.
"Why" im posting it in a elite section? well since only thing that can be seen of you is the bobber from time to time that is even then partially somehow covered or very well hidden, your fishing line wont be seen and since you are completely under water you wont be seen either, unless someone moves near you that has that lifebars thingy activated ^^
Here are the pictures showing the location in detail
Well you stand in the spot shown, and face with your char in the direction that is marked by the red arrows.
This spot aint perfect to "speed fish" since you will be getting some "cant fish messages" (like 3 out of 10 trys) but still i had around 900 bites in 45 minutes using MrFishit there.
In this spot you will fish up
you seeme to be underwater standing there but you WONT drown there.