under the weather rat

Question
Hello, my rat, Louigi, seems to be a bit under the weather. He is usually a very happy exciitable rat and is only a few months old. However, he just seems a bit down today and i wondered if this might be a sign of something else. I cannot see any swelling, cuts or anything else unusual, just a bit off colour really. He is a white dunbo rat with ruby eyes.
Thanks for your time!
best wishes, Lara.

Answer
 As long as he isn't showing any specific symptoms he's probably just fine, just keep an eye on him for any symptoms of illness.  It's also possible that he is just getting older and slowing down; males usually get much more laid back and lazy around 5-8 months so if he is around that age he may just be exhibiting the typical male laziness.  Hopefully this is the case and he is just fine!  Good luck!