Fear Agression/Anxiety in Jack Russell Mix

So I am desperately trying to figure out what to do with my 8 1/2 year old Jack Russell Mix (Milo). We adopted him when he was two. He was very skinny and scared and not socialized. He was always anxious and never really into other dogs, but would play with them every so often. As he has gotten older, his anxiety has increased. We got another dog when he was four, and after a while, they ended up liking each others' company and playing. She unfortunately died only two years later, and he was obviously disturbed by it. He seemed more anxious on walks and lonely, so we decided to get another dog. This dog, however, was younger, and they have never really taken to each other. Milo growls every time the other one walks by him. They generally just ignore and avoid each other.

Milo has also increasingly gotten fearful of pretty much everything. He has good and bad times, but he is always anxious. He will growl when being pet, even if he likes it because when you stop, he'll nudge you to continue. I know that it is fear based because when he is in this mood, you can call him over and he will slink over with his head down, ears back and crouched over, for no reason, even when calling him in an upbeat way. The only time he seems to be relaxed is right when we get home and he is super excited and affectionate or when he is playing with sticks.

I feel like we have tried everything training-wise. We took him a behaviorist who prescribed him prozac and gave us training tips. We instituted daily obedience, walking in heal, sitting and waiting for food until released, etc. At 20 pounds, his final dose of prozac was 20mg per day. After several months, we saw no changes except increased fatigue, so we stopped the meds, but continued with the training. We have seen no change in his anxiety. We recently started him on clomipramine (25mg per day) It's been three weeks and no change whatsoever.

I am looking for any help that I can get whether training or medication advice.

[Dan Sims, DVM]

This website will put you in contact with Dr Nielson, a specialist in behavioral issues.
http://www.animalbehaviorclinic.net/