I just received a 10 inch (plus) red-bellied Pacu and a Pleco (common) as a gift. I presently have them both in a 29 gallon. What size should I buy as I fell in love with Matthew (I've named him this---he seems SO sweet!--Pacu) I want to keep him (and the pleco) and was wondering if I should get him a tank-mate (of same size/breed). Also, I have had him for approx. 1 month and he was healthy when he was introduced to the tank, but now has an open sore on his nose and a slit above each eye. I have been giving a tsp of "Melafix" each day for the past 5 days (nothing seems to be healing!). He is a ravenous eater (the previous owner was feeding him ONLY feeder fish---after researching this species on-line, I realized he was an omnivore and have since offered him bananas/berries/grapes/peas---which he LOVED and I also supplement with feeder-fish occassionally---he seems to love the thrill of "hunting")and has not stopped eating, but I do want to keep him and will buy whatever tank necessary to get/keep him healthy. I think I should take a few tests of the water? If so, can someone give me some advice as to what levels these fish (and the pleco) would flourish at? THANK YOU!!!!! (FYI---I have kept small community tanks before, but I never knew how much I would love these giants!!!) -Paigey