Putting them together will be ok if you teached him but if you didn't properly train him, it could be a risk
If supervised when first introduced. Danes are generaly good with other pets. I have 6 Danes in my home with 2 cats,a ferret,a cockatiel,and two children. Everyone gets along geat.
introduction is always first. be very carful of overhyper small cats,children,dogs,etc.around your big dog. if so then keep a look out. mine cant be with my dogue de bordeaux because my great dane is old and doesnt want to fool with an overactive dog smaller than her
I really believe it depends on the personality of the two dogs. I had my daughter's dog when I first got my dane, and he is a mix about the size of a beagle. They didn't play much with each other because of the size difference, but they got along just fine. My son's dog is a dobie/rott mix, small enough to walk underneath the dane, and they play together all the time.
I have two very large danes and two tcup dogs. have had them all for two years now and nevr had any problems with the danes stepping on them.