I give a gentle but serious warning to you about Tennessee. He will do it again. You have a bird that in nature would be killed immediately.
I have 7 budgies, 2 very sweet ones of the 7. Every single bird I put with Hopalong stepped on her tail, held her down and pecked her backside. Also they all pushed her off the perch and made her cower in the corner on the grate, all day I figured from the way they treated her when we were home.
Once we put her by herself she gained weight and began sitting on the highest perch. They chirp back and forth all the time, but they will attack her first chance they get.
They are not mean or hateful, just animals who do what they are supposed to, get rid of the weak ones.
Please don't take this personal. I hope it works out for you, Tennessee and Harper.