Irradiated Roach
Source: Pet Battle. Most creatures cannot withstand a fraction of the harsh conditions that roaches can thrive in. Critter type. Actually go down into Gnomer to find these little buggers (no pun intended). Not in the instance, but right outside, near the where new gnomes wake up.
The Irradiated Roach is a wild battle pet found in the underground non-instanced area of Gnomeregan in the Eastern Kingdoms, and is notoriously difficult to find due to its low spawn rate and rare quality being hard to identify.
Guide awaiting review
Enter Underground Gnomeregan
Head to Gnomeregan and go down into the underground non-instanced area — do not enter the dungeon instance itself. Horde players with no Alliance characters should roll a new Gnome to access this area, since pets are account-wide and your existing pets will carry over regardless of the new character's level.
Find Roach Spawn Rooms
The Irradiated Roach spawns specifically in The Loading Room (south middle room), the area south of the hallway leading west toward the instance portal, and The Old Dormitory (west sub-room of the large oval Train Depot room to the north). The Wowhead map location is incorrect — roaches are only found in these underground rooms, not on the Toxic Airfield above.
Identify Rare Quality Roaches
All Irradiated Roaches spawn at Level 1, but health points do not reliably indicate quality — Uncommon roaches have been found at 132, 134, and 138 HP, while a Rare was found at 137 HP, so capture any unfamiliar health value to check its quality. Spawns are most commonly found in early morning hours and following server restarts, and respawn rates are very low, so logging out and returning after roughly an hour can help reset available spawns.
Tips
You will likely encounter many Fluxfire Felines in the area before finding a single Irradiated Roach — this is normal given how scarce the roach spawns are.
For a visual walkthrough of the spawn locations, see the video guide linked with this pet.
