When one wolf eats another, thee is nothing to eat in the wood.
More Spanish Proverbs:
One hand washes the other, and both the face.Spanish
Say nothing when you give -- only when you receive.
Spanish
Love can do much, money can do more.
Spanish
There is no pleasure but palls, and the more so if it costs nothing.
Spanish
A bad wound may be cured, bad repute kills.
Spanish
Better sit idle than work for naught.
Spanish