Less than a week ago, I acquired three baby valley garter snakes. They are only a few weeks old and were fed live fish previously. All three are housed together in a 20 gal tank with a warm side of ~85 (floor temp - there are lots of ways for them to get up closer to be warmer, which they often do) and a cool side of ~75.

Two of the three have quickly taken to eating cut up silversides and nightcrawlers (I have also started offering pinky pieces as well, but neither have taken any yet and I haven't bothered to try to convince them so far). The third shows no interest. He seems scared when food is wiggled at him with tongs and shows no interest at all when the only movement from the food is the worm pieces twitching.

I purchased a live fish for him yesterday and placed him in a separate deli cup with it and several other pieces of food (I don't want my less picky eaters risking the parasites from live fish). He was very interested in this and tried to grab it several times. He missed as it was flopping crazily and grabbed a worm instead. He then ate his worm piece. He afterwards bit the almost dead fish a couple times before deciding not to eat it (it may have been too large after his worm piece). He did not eat anything else after. Today I tried giving him worm pieces, cut up fish, and pinky parts again, but he had no interest.

What would be the best way to get him to eat? Should I just give in to his desire to have live fish present during his meals for now? If he was bigger I'd be far less concerned about refusals and I'm sure that not trying so hard would reduce his stress - at what point does not eating endanger him?