A full reading for Rat × Pisces meeting Rat × Capricorn is on the way. In the meantime, the score above is computed from the canonical element matrix and sign-cycle distance, and the profiles below cover each side individually.
The Rat/Pisces is half of the whole picture. As a member of this sign, you prefer to function as one of a two-person team. In the best case scenario the other person is the permanent love interest (marriage is very much in favor with you nesting homebodies). In every other case the second person will be found outside of the love relationship -- perhaps taking the identity of a co-worker, mentor, or friend.
Power for its own sake, and the cold brutal solitary serenity that accompanies such an exalted position, are precisely what the Rat/Capricorn lives for. If they think they've seen goals-oriented people in action before, they haven't seen anything until they've seen the Rat in you breeze past them on your way to the top, in such a way as to make Genghis Khan seem mild-mannered, of whatever hierarchy to which you see fit to belong.