Tropical fish eating goldfish?

So I did a big no no and have tropical fish mixed in with my goldfish in my 75 gallon tank. One of my tropical fish has gotten big enough that it bullies the larger Goldfish. He has eaten most of the fin and tail and now just latches on and nibbles. It looks vicious to watch and I feel somewhat guilty. I don't necessary want to separate or remove the misbehaving fish but was wondering if this is common and should I accept the circle of life?