NOTE: This is in no way ridiculing anyone, especially experienced hobbyists in any way. "tAnGs ArE aCtIvE sWiMmErS". Yes, I know they are and so does my neighbor who keeps a yellow in a 55 (has done so for 8 years), and my LFS who keeps 3 purples in a 300 and another with one in a 175. The thing is that they are perfectly healthy and big, but I swear... from the ones I observed, all that space they have to swim around and they seem to just prefer staying in that 1/8 portion of the tank just swimming around the same rocks . All this just has me thinking... is such a large tank essential in case u get a tang that truly just prefers to hang around one spot?