Nice to have you on the forum. I don't know how close Sunderland, NE is to Omaha/Council Bluffs but if you get here I will let you have a pair or 2 of my beautiful T.radix(Plaines Garter Snake) Just let me know. The care sheet is a good place to start looking for what you need.
I just checked and saw you are in the middle of the State. Not very close but my offer still stands.
wrong NE I think - hence wrong Sunderland as well
rhea "you cannot depend on your eyes when your imagination is out of focus" Mark Twain
What size aquarium around and will it need to be heated?
As big as possible really garters are very active and love to explore. I would say a three foot tank as a minimum for an adult female. Being in Britain you will need to provide a warm spot without a doubt. Make sure it's on a thermostat and the snake has the choice of a warm spot of about 30C and 20C at the opposite end of the tank.
I know goldfish and frogs, but what is the best food and how often?
Best food available here in britain would be a mixed diet of pinky mice (fluffs for larger snakes) and frozen/thawed trout or salmon fillet. (with occaisional vitamin and calcium supplements) this is easy to cut into portions and store in the freezer.
Adults should be fed approx twice a week with young snakes eating every two to three days. Garters have a higher metabolism than other snakes.
What sort of stuff should I be putting in the aquarium(stones,Water etc.)
A nice large waterbowl, lots of hiding places (plastic plants are good for this in addition to a hide) and branchy things for it to climb.
Any other important information would be greatly received!!
They're fantastic snakes and you've come to the right site. Have a good look around the forum and you'll find plenty of interesting information