Hey everyone, firstly i wanna say thanks to all the people that contribute tp this site, its amazing! Im currently living in Bangkok and am wanting to buy what they call a common octopus (i dont think they know what theyre talking about). The octopus and cuttlefish specimens here are caught by fishermen who then sell them to pet shops, ive seen them im bad condition, injured and even dead... But some places seem to know what their talking about. i love these clever creatures and i dont want to be the one responsible for their death, and although ive done some reading i thought ide ask some more questions for clarification. Ill start with what i have..(i dont really know the names for everything though) i have a 50 litre tank with a filter (the regular type thats inbuilt to the tank and lets the water through the top) ive been keeping a few hardy fish species like clownfish, razor fish and 2 seahorses. i have nice ocean coral rocks with holes and crevices empty clams and crushed coral for the base. Now i want to add what they call a common octopus from 3 to 6 inches in lenth, the markets tell me that they get them from fisherman on the eastern side of Thailand, i think its called the Gulf of Thailand. 1. What species could this be? 2. Ive tested the Nitrate, how essential is it to test for all the other bad stuff? (the fish shops tell me i dont need to). 3. Should i upgrade to a larger external "HARDCORE" filter? 4. I change about 20% of the water weekly, everything in there is living well, can i assume that an octopus will too? 5. i have an air conditioner on at night, the fish handle it fine, will this kill the octopus? 6. Ive seen that they keep octopuses together and even octopuses and cuttlefish together.. is it really possible? thanks guys... its amazing the pets that can be bought here soooo cheap too. Octopuses are $4-$6 and you can also get cheap tiger cuttlefish, and wehat they call red ring, green ring and blue ring octopuses.. as well as the Ceph that live in the shell ( excuse my ignorance ).