I had an octopus actually I had two of them...
They are hard to keep.... but there not.... if that makes any sense! lol
They are not something you can sit around and watch all the time so if thats why you want one then its a waste of your time and possibly his/her life.
You have to keep up on cleaning the tank thats a def! they are messy and most of the time the chunks of food left over are large enough to get stuck in the rocks etc. They NEED plenty of places to hide as well therefore you wont be seeing it too often! I have had a VERY tiny one that was no bigger than my thumb and I also had a larger one with a head about the size of my fist. I had them at seperate times and they were the only creatures in the tank as well.... They both lived in a 45 gallon tank... and it seemed to be plenty of room for them esp the smaller one of course and the larger one did pretty good too... on many pages they say that they will most likely live a year or two my smaller one did a little over a year and my larger one almost made it to three! but also you have to remember I have no idea how old they were or how long they were in captivity before I had them. The type I had was a Bali and they seemed to be pretty good ones to choose. If you need anythign let me know
Davis_403@comcast.net
Good luck.....
