What can i do for my Canary No vet in area?

He once was a fantastic singer for the first five months we had him ... all of the sudden he stop singing for about 1 month now ... bird droppings are watery and loose ... seems to be on the perch alot with feathers puffed up ... seems to be very weak as have hard time flying to next perch ... he is approx 1 year old. He has plenty of canary food and water in cage. He is eating his food. We have place vitamins on his food. It not molting season yet as he has all feather. He staying on the floor of cage feathers puffed and there is no drafts in the room . We have a budgie in same room who 7 years old and doing just fine and of course in separate cage. What can i do for this canary??