another feeding question ( sorry )

[VenomdeBeever]

Hi every1 nice to meet you.

This is my new guy Marley Checkerd garter Thamnophis marcianus. I got it from Critters in allenpark MI. They told me that the rosy red minows they sale there are ok for my snake so thats what ive been feeding him since I got him 3 weeks ago. Hes eaten 3 time the first 2 times was 1 rosy red minnow, the 3rd time was 2 of them. I also have a full skin shed from him too. Well after research I am now worried about my new little guy dying.

What can I do and what would be a good diet of multiple food sources for him. I have 18 Tarantulas too and breed cockroaches and crickets for multiple food sources for my Ts I know not to feed the roaches or crickets to my snake cause they have alot of trouble digesting insects. & what can i do to get his B-1 back up.
Heres a pic of the minnows and a pic of him or her ohya and a youtube vid of me petting him or her.
YouTube - ‪Checkered Garter Snake ( Thamnophis Marcianus ) Marley‬‏