Have a look at the plantgeek site. It says they are best in a paludarium, which is a polite way of saying they are best emersed in a moist atmoshere. There are a number of anubias sp. and many of them are quite large. I know a person who grows quite a few of the rarer ones and they are all emersed. The rootstock should not be buried and they are generally slow growers so are subject to problems with algae. Having said that I must admit I don't grow them. I tried growing nana emersed but it croaked in my set up ---to dry.