I personally wouldn't put angels in a 40b because of the tank height - just 16". I had a single male angel (after he killed my female) in a 25g which was 20"H with rummy nose tetras. The rummys stayed in the bottom half of the tank and the angel liked the top half. He was a marble koi and got very large. Maybe if you had a smaller variety, they would do OK, but my angel would not have fared well in the shorter tank.