The main symptoms of arthritis in RABBITS are:

Preference to stay put: When moving hurts, your rabbit will prefer to sit still. Makes sense right?  
 
Stiffness: In particular after lying down.
 
Wet belly: Arthritis can make your rabbit incapable of taking on it’s usual position when peeing.. 
 
Eating less: Arthritis may cause your rabbit to stop eating as much as he used to.  
 
Aggression: Don’t take it personal, your rabbit is just in pain.  
 
What can I do when my rabbit has arthritis? 
Unfortunately there is no cure for arthritis. What you can do as a rabbit owner is: watch your rabbit’s diet (avoid ovewreight), keep your rabbit warm, and keep your rabbit clean. To ease the pain, you can also consider giving your rabbit CBD.