Nem's planet
From The Stargate Omnipedia
World inhabited by at least one member of the Oannes race, Nem. The world is one of at least four planets orbiting a gas giant. Pockets of volcanic gasses litter the land. Near the Stargate lies a sea where Nem resides.
DETAILS
HOME TO - Nem
FIRST APPEARED - Fire and Water
KEY EPISODE
Fire and Water - SG-1 travels to Nem's planet and encounters the member of the Oannes, who captures and convinces them that Daniel is dead -- so he may take his time in extracting information from the archeologist.