One of my rats recently got diagnosed with lung tumor. The vet gave me antibiotics and said that he would likely die within 1-3 months. Originally he had been on antibiotics before for what we thought was just a cold, but it progressively got worse to I kept taking him back to the vet. Seemingly very suddenly one night he started coughing up blood, so much that it even came out of his nose. I rushed him to the vet the next morning after it seemed he was still acting normal and that's when I got the diagnoses. Since then he is still on antibiotics but at most that just seems to be a pain killer. He can't eat well, I have to wet his food so he can swallow it since he has issues breathing and he's lost weight because of this, he coughs and sneezes blood, he sleeps a majority of the time, he's started to walk funny, half of the time he doesn't come up to the cage anymore when I go up to it and he squeaks at his cage mates when they come near him. Half of the time he also seems lethargic, but the other half he seems somewhat normal. Writing this I've already decided that euthanasia is probably going to be the best option for him. I'm having a hard time coping with the decision, but in the past week I've already seen him progressively get in a worse condition than before and I don't want to wait until he is suffering to do it. Would anyone have any advice for me? Is it too soon? I'm most afraid of cutting his life too short. Currently he is very sick, and he'll have to be on antibiotics for the remainder of his natural life if I do choose to keep him alive. I think if I wait another month or so to do it, he will have already deteriorated so much that he will be suffering. Any advice is welcome, thank you. UPDATE (10/11/2018) I took him to the vet this morning and officially got X-Rays done on his chest so we could more properly assess the damage. Before the vet was just assuming. He does have a tumor, and it's in his chest cavity, between his lungs and heart. There is some good news though, now that we know for sure that it's a tumor it can be treated with steroids to shrink it some to make him more comfortable and buy him a little more time. The steroids are already seeming to make him feel a lot more lively than he did these past couple of days. What I was giving him before was just Orbax, which at this point only seemed to be doing something for the pain slightly. I know that in the future I'll have to put him down probably. The vet recommended going through the entire bottle of steroids and seeing where he's at then. After the steroids run out they recommended for nature to take it's course and see how he's progressed. Thank you to all of you that commented and helped me, I loved reading your responses and they brought me some peace of mind through this tough process. One more thing! There's a photographer around here that does pet photography for pets with terminal illnesses so I'll be taking some pictures with him in the near future. I want to make sure I have good memories with him. I'll make sure to post some when I get them!