They are preds, like Datnoids. Ours just hovers on the outskirts an does'nt really move 'til there's something to go after. Looks good, though. We're hoping to grow it out to 10", about max.
They're schooling fish that don't get along with each other unless there are several of them together. Individually they do fine, and are okay with other species as long the others are'nt small enough to eat.
They can hover in the background and watch dithers forever.