Confusing behavior from our new dog

[vanallen25]

Thank you for your input, I hope this issue can be resolved quickly, the poor cat wont come out from under the couch and that is really not like him. Our Kitty had a very outgoing and lovable personality, now he is always scared.
thanks again.

[Giselle]

Time helps heal almost everything. Going from a single animal house to a multi-animal house is the biggest step. Going from 2 to 3 isn't hard, but it IS hard going from 1 to 2 Good luck and just have a little patience.

I remember my boss would always chant to herself, " I... am a fountain of patience. Everything I do, everything I say is an extension of my patience. Patience will flow forth from me."

[Varga]

Hmm.. You said the dogs tail is wagging? Is there any chance that the dog perhaps is trying to get the cat to play with her? It's not uncommon for dogs to growl etc. when they play together. You did mention her hackles were raised as well.. which a lot of the time is a sign of anger but I have seen dogs raise their hackles when they play as well.

Not saying it couldn't be fear aggression tho'. But the barking and tailwagging got me thinking about my Leo and Taggart, so I just thought I should give my two cents

I have two dogs and a cat myself, so I've seen my dog Taggart trying to play with the cat several times. He'll do almost exactly the same as you described. Bark, growl, wag his tail and "punch" the cat with his paws and of course do the typical doggy play bow as well. Does your dog do the bow as well?
Most of the time the cat just ignores him (he's grown up with dogs, so he's used to them acting stupid :P). Your cat is probably reacting by hissing and getting scared because he isn't used to dogs trying to play with him so he interprets it as a threat.