If I'm understanding correctly you can use an array 'for loop' to run through X,Y where X=1 and Y = loopindex while you look for the fish name, if curY = "fish" then stop loop and add 1 to x=2,y=loopindex.
Note : I find it easier to do it where X row is the new fish and Y columns are the values, although it looks backwards in the array file I find it just makes more sense in events but that's up to you...