How long will it be until the 100 gallon arrives? Once you get that I would but the JD in there with the Pacu's. How long have they been together? I got a baby JD a couple weeks ago and he to spends most of his time hiding but he does come out to eat. Once way you can make sure that food gets to him you could go to the store and get a turkey baster then just find were he is and squirt some food down there for him. As far as if the pacu's will grow once in a bigger tank I would imagine they will some but I doubt they will ever get to there full potential. I wish you luck and hope you can find homes for the remaining pacu
WOW!! Now THAT is impressive! I'm almost jealous but with a family of 7, 4 (soon to be 5) active tanks, 3 dogs, 2 horses and a cat, I think we're good for now.