Fishes Fed means the amount of times you died drownin, they just call it Fishes Fed to sound "gangster-ish"
As for the wheelies, Sanchez's can balance themselves out, when it does, you dont need to press up or down, just try to go straight and slow as possible (use little taps of the accelerator like every 5 secs) But its near impossible to sterr left a right, I got 112 secs, and i could have got well over triple that, but I really can't b bothered