Here's what I think. You got your FH probably as a showcase fish. A centerpiece fish if you will. FH's are valued upon their color intensity and condition of their finnage.
Why let a common wild fish destroy what you've got? Seperate any way you can, and power feed that FH.
I caught a greeen sunfish once (with two styrofoam cups!!!

) when my family and I went fishing. We were trying to hook catfish but couldn't. I saw the little guy hiding in some plants by the shore. Everytime I missed with the cups, it would come back a few minutes later, until I got him.
Took him home (he survived quite a long trip to get home) and kept it with a RD that was larger than him. He not only outgrew the RD (as far as rate) but he was constantly battling the RD.
Very cool fish... aggro, 'hits' the food you give it like a sport fish.
You're right about the chompers senor pescados. When I had mine, I took it out a couple times to hold it by the jaw as if I caught it with line and reel, and my thumb was always left with lines from where the teeth cut my skin!