I had that problem too. At the foggy lake use your old rod. They will only be in four
squares and only in those four squares half the time. So encounter two pokemon in each
square with an old rod and move on. The squares change daily so it is difficult. I just
migrated mine from my emerald.

what four squares? and do you mean the lake south from snowpoint and right when you see
the rock that you vcan smash? i dont get it and all i catch is magikarp

One step is a square. This might take ages , since
it is a HUGE lake. Good Luck , I will try this too.

? what squares!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

I spent Ihr lokking for feebas. And i used a super rod so i ran into a lot of gyrados.