The idiom "you're a peach" usually refers to someone being helpful, sweet, or thoughtful. It's a term of endearment used to express gratitude or appreciation for someone's kindness or generosity
When you see them in a tank, that is for their isolation period, and not their actual cage. Secondly, there is a bit of porphyrin on sticky's nose (the blonde one) because she had a cold, but she is better now :D