Hi! I had 3 4-5" tinfoils in my 55 with a pair of 9-11" reds for almost a year.The tinfoils would get a nipped tail fin once in a while,but they never got any serious damage.The P's couldn't catch them,and the P's were well fed.I did get rid of the tinfoils eventually though cause they got hellish big.I gave them to a buddy who has a 275 gallon.
Hope this helps.
I don't think so!
I do not know to much about the character of your Reds but my Cariba can't stand anything around!
Still, i've heard about people succesfully doing that since they keep their Ps very well fed!