I'm curious of the notable personality differences when kept in 40b and 55, (Example: more aggression when kept in a 40b, but more active in the 55) since they seem to interchange in terms of minimal tank size. I plan to keep one as a wetpet. I currently have a 40b, however I am willing to get a 55 if needed. As far as I'm aware they can be kept in 40b as long as they are alone, if not, please tell me otherwise.