Can i put my rogers sim card into a phone from fido?

You could but it wouldn't work. The Fido phone would have to be unlocked 1st for any other SIM to work in it.

You can swap sim cards in LG Gossip if the phone is unlocked. If it locked, I suggest you can approach Simpleunlocking.com and specify the country,locked network of LG Gossip. Based on the availability you can get the permanent unlock service along with free instructions.