I know this is a much discussed topic, but I can't make any sense of it. Officially a 48" 40B is good, but I had a common grow to 11", and outgrow a 55g. I have 2x 10s 1x 55 (in use), 1x 90, and a planned aquaponics setup, maybe 800g. I currently want wakins the way some people want asian arowana, and I know they are capable of swimming, which I like, but are they fancies that stay small? I had 6" comets too, and they were killed by finrot, so I don't know if they'd outgrow a 55 or not. What size do I need for wakins? Please don't tell me a 40B. At that rate, I might as well get an arapaima for my 55, it'll be just as happy.