For the fish oil you should go with 500 mg per every 20 pounds of body weight of the dog, once per day. You can increase this up to 500 mg per every 10 pounds of body weight of the dog, once per day once you see how they respond to it (I.e. make sure it does not cause stomach upset or something along those lines).
For the glucosamine you should go with 500 mg per every 25 pounds of body weight of the dog, once per day.
You can always consult your vet as well if you want to make sure that the dosage is tailored to your dog specifically (I.e. some dogs have medical conditions or other factors that may make the vet want to adjust the dosage of such dietary supplements from the standard dose).
