Just asking but where exactily are you gonna put them? If those are your tanks in your signature then when those fish get bigger in the 55 then you are gonna have probablems as it is.
Oh sounds good then but even in a 280 gallon I still dont think that clown knife could go with the others. Those tinfoils may could outgrow that 40 gallon. If you get that 280 I would put them in there with like the oscar and depsey and keep some of those fish in the 55. Goodluck with your new fish.