Hi all. I acquired three (3) beautiful Eastern Box Turtles, 1.1.1, about two months ago I'm in SoCal and I keep them in a 5' x 6' outdoor enclosure. They are all active, friendly, with good appetites.
However, yesterday I noticed the male has a wet nose with bubbles appearing from his nostrils. When I picked him up, he emitted a high-pitched wheezing sound. (He normally hisses when I pick him up, and is more reticent than the other two turtles). I'm assuming he has a cold, some sort of infection. What treatment should I give him at this point, if any?
He is still active and seems to have a good appetite. Yesterday and today I noticed that he was actively exploring the pen and checking out the other two turtles. He devoured the bananas and strawberries I put down in front of him.
Any suggestions as to what I should do? Thanks in advance.

