i highly recommend a sunflora from route 4. its already high level and will really help vs the water gym too and if you level it up some it learns sunny day which gets rid of the feild effect for 5 turns so theres that. other than that id say ditch medicham and grab a makuhita and level it up, as hariyama is one of the strongest fighting types in game that ive seen.( unless u can get a iron fist hitmonchan since that can learn fighting, fire, ice, and electric type moves,which gives it amazing coverage and iron fist cuz they're all punch moves.) sharpedo is pretty good but if ur gonna use it get about 10 reverse candies and get the carvanha to 15 so you can get it to relearn Aqua Jet at 16. also look into that mareep from the hotel in gearan, it learns t-wave and c-ray so you can parafusion the hell out of them and lol while u thunderbolt their faces off .