I have a level ~27 Poliwhirl from the Grotto in Route 4. It has good stats, physical and special are both good, but I want a physical Poliwrath. The current moveset is: Body Slam, BBeam, RDance and Hypnosis. How can I get a good moveset? (I want Waterfall, but that doesn’t seem possible?)
Any other physical water moves I can get? Or, should I get the Custom Move made (although I want that to be reserved for my Zebstrika)?
Custom Move is your best bet unless you chain breed for Waterfall (Goldeen/Seaking > Alomomola > Poliwag Line).
what abt special poliwrath?
You probably would need a Choice Specs or Life Orb for that. You could try a tanky leftover set with scald and circle throw but the TM scald can only be obtained after mid game.