I made my 29g tank for a small species of octopus but have a big tank planned out if it grows too much. I started off with live rocks and macro, mid-feb. Added a lot of amphipods, copepods, breeding snails and crabs. There are also covered hides so I can see octopus by lifting a piece of paper taped to outside of tank. Just got an algae octopus as the Caribbean ones I wanted weren’t available. Focusing on healthy tank parameters and the whole life cycle really help keep a healthy tank. (I’ve raised seahorses and cuttlefish and have a reef tank so not new to this.) I ended up using a standard tank and using foam and plastic sewing canvas to protect octopuses arms from intakes and from escaping. I have a glass top and cut and glued plastic canvas to firmly close holes.
