I am rather shocked, and would think it far more of a reaction to the green "terror" then to the silver dollars! The silver dollars should be about as threatening to the Jag and Pike (Cichlid I assume) as a banana is to a chimp!
If removing anything I would think the GT and pleco should be your first choice.
In another thread I have what can only be described as the most timid Jag her on MFK! With that said, >long story short< after being beaten mercilessly by every tankmate I had it with, I had to treat it in my hospital/ QT tank!
I could not resist the $1 silver dollar sale at Petsmart, but knew I still had to quaranteen them before intrduction to a community tank. The SD's were around an inch to 1.5 inches smaller then the jag. I ploped them in the tank, and the first S.D. was dead before I could even blink. Before I could even get the net back into the tank to "save" the second SD, my "timid" jag had grabbed it and was repetitvely slamming it against the glass on the side of the tank! I was honest and DID NOT recieve replacement S.D's from Petsmart for my stupidity.
I think that your Jag and Pike have just agreed to allow the S.D.'s to gutload before the slaughter!
I know alot of folk do not like to feed live, but if you quaranteen correctly and are not morally opposed to the practice, you will easily be able to get you Jag and Pike eating like mad!
The drawback is it is sometime difficult to get fish to take non-live once they get the taste for the kill.
If I had to guess, I would say that the dude lied to you and they were eating live all along. It could take some time to convert off live. Only one way to find out!