I already posted on that other thread you have, but to add to my post..... I smaller clown should be added with the clown you have now. 1/2 the size of your clown should work out nice. What your doing is setting up the new comer for a fall in rank so to avoid over stressing him/her I would look for a smaller clown in a tank at the LFS who is NOT the dominant fish. A dominant fish being thrown into new surrounding with even more dominant larger fish adds alot of stress to the already stressful situation. IMO