prolly need around a 30 for a full grown peacock, and I would suggest an acrylic tank also. For filtration I really don't have any other than water changes and a lot of good live rock. Lighting, well they don't really require much, I just have a simple normal output 50-50 bulb, i've heard too much intense lighting will lead to shell rot.... I've got pics of my tank somewhere on the pic thread in this forum.