this probably seems like a dumb question but im kinda new to this piranha stuff. ive only had my rbp's for about 3 weeks. got 1 inchers (5 of them) in a 55 gallon. i was just wondering if theyre big enough to eat feeders yet. and if not, how big should they be when i start to? one more thing, can i mix rbp's and spilos? should one be bigger? thx