Get the aquarium salt. I call it twirling disease, they lay on their side and get like this. I managed to catch it early last time, I used heated aquarium water in QT with aquarium salt. He seemed to perk up, Then I believe it might be a bacterial infection from what I found on the internet. Then start meds for a bacterial. He ended up back at the store because I didn't want him to die. But he did survive overnight and the lady said she would try to save him.