How do you evolve Onix?

Into Steelix: Trade holding Metal Coat (Z-A, BD/SP, Sw/Sh, US/UM, S/M, OR/AS, X/Y, B/W, HG/SS, D/P/Pt, FR/LG, R/S/E, Gen 2); Use Metal Coat (Arceus).

Onix is a dual Rock/Ground type Pokémon.

What is Onix weak to?

Onix is Rock/Ground. It takes 4× from Water and Grass and 2× from Ice, Fighting, Ground and Steel.

No. 0095 · Gen 1

Impish: Raises its best defense and drops Sp. Atk, which it won't use.

Hit ONIX with Water and Grass for 4× damage. Ice, Fighting, Ground and Steel also deal 2×.

4×Hits hardest

2×Super effective

½×Not very effective

¼×Barely scratches it

0×No effect

In Pokémon GO: Water deals 2.56× instead of 4×. GO chart

ImpishRaises its best defense and drops Sp. Atk, which it won't use.

Worked out from base stats. Your team may need something else.

Defeating Onix gives 1 Defense EV.

Your game

OnixRockGround

Trade holding Metal CoatZ-A, BD/SP, Sw/Sh, US/UM, S/M, OR/AS, X/Y, B/W, HG/SS, D/P/Pt, FR/LG, R/S/E, Gen 2Use Metal CoatArceus
SteelixSteelGround

The strongest attacking move it can learn in each type, across all games. Not every game has every move. Same-type moves get a 1.5× bonus.

Type	Move	Kind	Power
Normal	Explosion	Physical	250
Rock	Head Smashsame type	Physical	150
Ground	Earthquakesame type	Physical	100
Steel	Iron Tail	Physical	100
Dragon	Dragon Pulse	Special	85
Fighting	Body Press	Physical	80
Dark	Brutal Swing	Physical	60

Regular Pokémon whose same-type moves hit it hard and who take little from its same-type moves. Picked from types and base stats only, not movesets.