You have to have water placement donation. And sponges. And fence. You place water 7 blocks from fence (so the last little bit gets on the fence), then place a sponge or two so the little tiny bit of water stays on the fences, then clear it all away and ta-da. Or if i wasn't helpful, go to tutorial area at the end (in donations section) there is a tutorial of it.
Well thats because fishing is the worst way to get money now in my opinion. It makes less than 3K and hour and I would suggest doing something else unless you had a good reason to fish like leveling up your mcMMO or getting loot.
