Onix does not evolve by leveling up, you must to trade it while it is holding the item Metal Coat and it will evolve as soon as it has been traded.
Chat with our AI personalities
Onix does not evolve by level. It can evolve by being traded while holding metal coat.
Level: Onix Evolves By Trading.
level it up
You have to trade him
onix has to be traded and be holding metal coat