Pom had a difficult start to his life. I got him from the local petstore with his brother Pim at age five weeks. Then he got an inner ear infection after two and a half weeks and I had to force antibiotics drops into his mouth with a syringe twice a day for 10 days. The infection left him with a permanent headtilt thanks to the petstore and greedy breeders. The woman from the petstore had the nerve to tell me that she thought that he wouldn't survive because he was so tiny when she sold him to me. This of course AFTER I told her what happened and showed her the vet bill. Which they (naturally!) didn't reimburse. I have the ability to make people casually tell the truth. Then his brother Pim suddenly died of unknown causes two weeks later.
I got him a new mate after three days which was a girl rat instead of a boy (I found it out 8 days later, so I had to remove her to another cage) and he was alone again for five days because I had to separate them. Then I finally got the right mate for him (his new mate Pingu II, the brother of Pingu I, the one that I had to swap), who is one and a half months younger.
Pom is clicker trained to get treats. Recently he learned to climb on my knees for treats when I crouch in front of the cage (when I click).
His favorite treats are biscuit and Crispy Toasties cheesesnacks. The rats get rat food and fruit every day and a treat when I wake up, and various small treats like biscuit or cheese during the day.
He can't use the tubes in the cage to climb down well because of his headtilt disability, so I made a ladder for him from 3 layers of half-inch mesh to climb down from the middle tier to the bottom.
Since he got bigger he got more active when I have him on my lap or on the couch. He used to be quite docile and doze off on my lap when he was smaller and still fit in one hand. And his nails are quite sharp now, which shows on my hands.