I have garters and don't care for them. Even at two years old they are still defensive, musk, and bite. My only successful escapee is a garter.
When they are tiny they eat small fish and night crawlers (get them from a bait shop), but as they get older you can switch them to mouse pinkies and then larger mice as they grow.
DO NOT FEED GOLDFISH, ROSIES, GUPPIES, FROZEN SILVERSIDES, OR ANY OTHER "FEEDER" FISH FROM A PET STORE - thiaminase is deadly and I lost one to it before switching to fresh tilapia "worms" (I ate the rest of the filet) along with night crawlers. I did use the fish to scent the mouse pinkies to get them switched over when they got big enough.