They must keep in lower tempreture-at lease>28, and best keep in pair. I have 1 pair of fire-gobies, 1 pair of purple fire gobies and 1 pair of helfrich fire gobies live for 6 months together, they seems very friendly.
PS. must have a glass top, even you don't have agressvie fish to chase them. If the light suddently turns on, they might be frightented.