Unfortunately one of my babies (from Julius & Mona's clutch of six) still hasn't eaten, and I'm starting to get a little worried. He hatched on 8/23 with a bit of unabsorbed yolk, finished the yolk about 4-5 days later, and shed on 9/3... hatch weight was 55g, then he spiked to around 63g after finishing the yolk, and is now back down to 53g. I've offered a rat pup and mouse hoppers of various sizes, and even tried leaving a f/t fuzzy in there overnight. He's normally healthy & active, but is looking kinda thin, so I'm wondering if it's time to assist feed? I watched some YouTube videos, and it doesn't seem that difficult. Or is it? Thought & suggestions would be appreciated!

P.S. Everyone else is eating GREAT, and haven't refused meals since their first feedings... each (other) baby has taken between 4-6 meals now, and are mostly weighing over 100g.