go in the oldchateau after 8 pm until (i think) 10 pm, and look in the old TV... its level is pretty low, so try using a low level Pokemon (i would suggest the move false swipe- but rotom is not affected!) around level 20 is good. to be sure save beforehand, so if you faint it you can try again.
Chat with our AI personalities
Actually, you can only get Rotom by trading in Diamond, Pearl, or Platinum at Toys R Us.
In Pokemon Diamond and Pearl and Platinum which are the newest versions on the DS until the newer ones you catch Rotom after you get the national pokedex. Then you can transform him into different types.
You cnnot catch it in Pokemon fire red ,but you can catch it in Pokemon Diamond and Pearl.If you want it to be in your fire red,you will have to migrate it from your Diamond/pearl to your fire red.
You cant do that in Pokemon pearl or diamond but you can in platinum!! From poke-know-it-all
Rotom wasn't created until Generation IV, so you can't; the closest would be Missingno. The only versions on which you can capture Rotom are Diamond, Pearl, and Platinum.