The parasites was only a guess, since the snake seems so skinny. Though, now that I look at it, the snake doesn't seem to feel secure in that large enclosure. If you have a large enclosure with a baby snake in it with an open space it's most likely not to eat due to stress. When you have a large enclosure, never have any open spaces because it would not make the BP feel secure. And since the BP is new, it may be stressed and still is trying to get used to it's surroundings so give it another 5-10 days to settle in (with disturbing it besides changing the water dish), then try to offer a food item.