Sad unfortunate update up the babies-https://www.reddit.com/r/PetMice/comments/1tfbyfq/update_on_the_weak_runt_of_the_litter/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button

I came to tend to the tank I keep them in (20 or 40gal) this mornning and found that sadly 2/4 passed away... I thought the second runt was big enough to not worry about and I was wrong. I believe the mom might be next because she's getting old and has visibly slowed down. I'll keep an eye on her and the rest of her babies