Well, as nait002 said, if you want to get one, get one with color. The whitish ones are usually in poor health. Second, if they do well, they will get very large, very quickly, attaining disc diameters of up to 24". So, in other words, you need to give them plenty of room. They do well when provided with reasonably bright lighting, coupled with a good feeding regimen, consisting of fish meats (the entire fish). Silversides work well for the latter purpose.