Petstore Rescue Attempt

[VanSickel_Balls]

"Handle with care" is what the box says. I was in a local Petco yesterday morning buying a few supplies when I decided to peek in their BP tanks. Horrified, I saw this sweet thing drastically underweight and being housed with 3 other BP's. A baby balls back should be rounded out and fully filled, not concave, allowing me to see its spine and ribcage throughout its back. I returned this morning. I was not going to leave it there to slowly starve to death. I confronted the store manager and he said they were having trouble getting them to eat. He lifted the rock hide and revealed the most skinny, malnourished animals I've ever seen in person. It was heartbreaking. If course, I couldn't save them all, but this little boy or girl has a fighting chance. I can't say the same for the others. He tried to assure me they would take the animals to the back for more "intensive care ", but if they were focused on providing adequate care in the first place, why did it take a customer to point out the serious condition of their animals at all?
I don't believe those other babies will last much longer, but with focused care and plenty of time, this little one may make it... I'm fairly certain he/she is a pastave, but let me know if you have any other guesses.
So my main question is, do any of you have experience bringing back BP's who were very underweight/in poor health? The little baby only weights 46 grams at the moment. It needs to eat, and I've offered it a live fuzzy using the paper bag method (which I've had success with before ), but it hasn't taken it so far. If it comes down to assist feeding, how would I go about that?
Thanks for any and all help in advance!