I beleive seabae and carpets. However, both are difficult when it comes to keeping them. But it is random what they will host and for that matter even whether they will host or not. For example, I have three pair one hosts a torch coral, another green hair algae, and the third a flower pot. In the past I have had them host mushrooms, a heater and a patch of green star polyps. So it kind of depends on the fish's personality.