In regards to Octopus please understand that while yes they are extremely interesting to watch, they CAN and usually are equally hard to care for. They will likely not live past a year (even in perfect conditions), they can eat everything you put in the tank, they are smarter than most anything else you could get, and if they can fit their beak through a hole then they can (and probably will) get their entire body through there. And this is not even getting into water quality, inking, stress, or the fact that some offered for sale are toxic enough to kill you... if you are going to buy one then please do your homework, but I agree they are amazing creatures to watch.