i m at the 5th gym and I need to train my joltik.
already thank you.
I would suggest Driftveil Drawbridge. There it is a 100% chance to encounter Ducklett, Lv 23-26, a Water/Flying type. Joltik should have no problem training there. Just look for the dark spots, they apper quite often. Furthermore, you will also have a pretty good chance to get Wings, wich can be used for EV training.
Source 1: http://pokemondb.net/location/unova-driftveil-drawbridge
Source 2: http://bulbapedia.bulbagarden.net/wiki/Wings
Source 3: http://bulbapedia.bulbagarden.net/wiki/Phenomenon#Flying_Pok.C3.A9mon.27s_shadow
Bolded Pokemon cannot be found in the wild.