AppearanceOnix is a Rock Snake Pokémon. Its serpentine body is made up of large boulders and little pebbles. It has a long horn atop its head and small eyes.
Onix can have the ability Rock Head or the ability Sturdy. Rock Head prevents Onix from recoiling. Sturdy gives Onix immunity to OHKO moves. When it is burrowing underground, it can cause rumbles and earthquakes. It can dig up to 50 MPH. It has a compass in its brain that can tell what direction Onix is facing.
In the anime
Main Article:"Brock's Steelix"
Brock received Steelix as an Onix from his father, Flint, on his 10th birthday, as seen in a flashback in Having a Wailord of a Time. Onix was Brock's 1st Pokémon and has consistently been his strongest.
Main Article:"Crystal Onix"
The Crystal Onix's first and only appearance is in the anime episode The Crystal Onix. Ash and his friends first heard of it through a note they found in a bottle floating in the ocean. The note was written by a little girl named Marissa. She wanted to find the Crystal Onix to help her brother, Mateo, gain inspiration to make glass Pokémon statues. Mateo told a story of how his grandfather discovered the Crystal Onix and then was able to make extraordinary sculptures afterwards. One of those sculptures included the Crystal Onix itself.
|Red/Blue||Rock Tunnel, Victory Road||Common|
|Yellow||Rock Tunnel, Victory Road||Uncommon|
|Gold/Silver||Rock Tunnel, Violet City, (trade Bellsprout), Mt. Silver, Victory Road, Union Cave||Common|
|Crystal||Rock Tunnel, Violet City, (trade Bellsprout), Mt. Silver, Victory Road, Union Cave||Common|
|FireRed/LeafGreen||Victory Road, Rock Tunnel, and Sevault Canyon||Common|
|Diamond/Pearl||Iron Island, Snowpoint Temple, Oreburgh Mine, Victory Road, Stark Mountain||Common|
|Platinum||Iron Island, Oreburgh Mine, Victory Road, Wayward Cave||Common|
|HeartGold/SoulSilver||Violet City (trade Bellsprout), Union Cave, Mt. Silver, Ragged Cliff Gate, Victory Road, Rock Tunnel||Common|
Side game locations
|Pokémon Trozei!||Phobos Drill, Endless Level 46, Forever Level 23, Mr. Who's Den|
|Red Rescue Team & Blue Rescue Team||Magma Cavern (21F-23F), Magma Cavern Pit (1F-2F), Southern Cavern (40F-50F)|
|Explorers of Time & Explorers of Darkness||Mt. Travail (1F-19F)|
Its name comes from "Onyx," a black stone that can be found in jewellery or it comes from the end of the word tectonics.
- Unshō Ishizuka, the actor best known for playing Professor Oak in the original Japanese version of the anime voices both Onix and its evolved form, Steelix in both the Japanese and English-language versions of the anime.
- Pokémon.com Pokédex
- Serebii.net Pokédex data
- Legendary Pokémon data
- The Pokémon Database
- Pokémon Dream Pokédex data
- Psypokes Psydex data