ssh - prompting for password even for non encryption key

Question

I wanted to do the ssh from my local machine to a remote server.

I tried with this: ssh user@server

I copied my private keys into .ssh/id_dsa into my user home directory, and see my private key is not encrypted as mentioned.

Please let me know how I can remove this prompt at the time of ssh to the remote.

FYI, when I tried to log in with it, it works without any prompt as mentioned.

ssh -i location-of-pkey user@server

Note - I already setup the remote server with my public key already.