If she isn't already in it, put Courtney into 1 tsp of aquarium salt per gallon in a little bowl. Pre dissolve the salt before adding Courtney.
fishychloe, it's important to remember to do 100% daily water changes as long as your bettas are in small containers with less than a gallon of water. When all your bettas are healthy again, we'll help you figure out permanent housing and a water change schedule for everyone, okay? Water changes are really important if you want to keep your betta babies healthy. :)