Hi there, and welcome! With all due respect to everyone else, I would suggest staying away from guppies and use them as a last resort if it will eat NOTHING else offered. The only snakes I have had problems with were ones that ate live (except for live earthworms) even if they were converted to mice later in life.

You can feed chopped NIGHTCRAWLERS, chopped fish filet (salmon, tilapia), and chopped pinky. Offer up chopped nightcrawler first, then if it takes that, go to the pinky or fish, with some wiggling worm parts on top. It should get the hang of it.

Please note that there is a difference between NIGHTCRAWLERS and RED WIGGLERS. Nightcrawlers are safe, but red wigglers are not. Red wigglers excrete a toxin, and will at the very least cause your snake to regurgitate it's meal, and can kill a snake. The difference between the two, the reds are smaller, and also have COLORED banding, red and yellow. Nightcrawlers have band-like ridges, but are the same greyish-pinkish through out.

Bait stores often sell both, as do the big chains, as other species like turtles can eat the reds no problem. Just ensure that you get nightcrawlers.

Best of luck with your new baby!